全文获取类型
收费全文 | 286篇 |
免费 | 6篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 44篇 |
金属工艺 | 10篇 |
机械仪表 | 5篇 |
建筑科学 | 6篇 |
能源动力 | 5篇 |
轻工业 | 17篇 |
水利工程 | 3篇 |
无线电 | 11篇 |
一般工业技术 | 34篇 |
冶金工业 | 107篇 |
原子能技术 | 4篇 |
自动化技术 | 43篇 |
出版年
2023年 | 1篇 |
2022年 | 5篇 |
2021年 | 8篇 |
2020年 | 2篇 |
2019年 | 5篇 |
2018年 | 6篇 |
2017年 | 4篇 |
2016年 | 4篇 |
2015年 | 1篇 |
2014年 | 4篇 |
2013年 | 12篇 |
2012年 | 12篇 |
2011年 | 17篇 |
2010年 | 17篇 |
2009年 | 14篇 |
2008年 | 13篇 |
2007年 | 16篇 |
2006年 | 9篇 |
2005年 | 10篇 |
2004年 | 4篇 |
2003年 | 7篇 |
2002年 | 13篇 |
2001年 | 6篇 |
2000年 | 7篇 |
1999年 | 9篇 |
1998年 | 21篇 |
1997年 | 15篇 |
1996年 | 9篇 |
1995年 | 5篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1989年 | 3篇 |
1987年 | 1篇 |
1986年 | 8篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有292条查询结果,搜索用时 15 毫秒
91.
Freeman Walter J.; Viana di Prisco Gonzalo; Davis G. Wesley; Whitney Timothy M. 《Canadian Metallurgical Quarterly》1983,97(1):12
Developed and evaluated an automated procedure for sniff detection in 4 experiments with 21 adult New Zealand white rabbits. The sniff was identified by a brief episode of increased respiratory rate, usually with a well-defined time of onset. It was detected against the background of respiratory activity in Ss simply, reliably, and noninvasively by statistical evaluation of digitized pneumograph records. The basal rate of exploratory sniffing was controlled by familiarization. Upon conditioning to olfactory cues, the rate of sniffing for CS+ increased sharply above the basal rate during the 1st trials and was maintained at high levels by continued reinforcement. During extinction with discrimination between olfactory cues, the rate for CS– fell sharply at first and then more slowly toward the basal rate. With pseudoconditioning, Ss responded to an unpaired odor after several sessions; the rates of response acquisition and extinction and the maintained level of responding were lower than with a paired odor in classical delayed conditioning, and the response was not discriminative in respect to another novel odor given during extinction. The sniff displayed a prominent sensory bias for olfactory cues. The relative frequencies of sniffing and respiratory slowing were measured as CRs by screening procedures with a small computer. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
92.
C De Cicco M Cremonesi A Luini M Bartolomei C Grana G Prisco V Galimberti P Calza G Viale U Veronesi G Paganelli 《Canadian Metallurgical Quarterly》1998,39(12):2080-2084
Lymphoscintigraphy associated with radioguided biopsy of the sentinel node (SN) is well established in clinical practice for melanoma. In breast cancer, the SN concept is similarly valid, and lymphoscintigraphy is a useful method for localizing the axillary SN. The aim of this study was to optimize the lymphoscintigraphy technique in association with a gamma ray detecting probe (GDP) for identifying and removing the SN in breast cancer patients. METHODS: Two-hundred fifty patients with operable breast tumor underwent lymphoscintigraphy before surgery. Three different size ranges of 99mTc-labeled colloid particles (<50, <80 and 200-1000 nm) were used, with either subdermal (above tumor) or peritumoral injection. Early and late scintigraphic images were obtained in anterior and oblique projections, and the skin projection of the detected SN was marked. Sentinel nodes were identified and removed with the aid of the GDP during breast surgery; they were tagged separately. Complete axillary dissection followed. In 40 patients, a blue dye was also administered in addition to subdermal radiolabeled colloid to compare blue dye mapping with lymphoscintigraphy localization. RESULTS: Lymphoscintigraphy successfully revealed lymphatic drainage in 245 of 250 patients (98%). The axillary SN was identified in 240 patients (96%). SN biopsy correctly predicted axillary node status in 234 of 240 patients (97.5%). Lymphoscintigraphy and GDP detected the SN most easily and consistently when 200-1000 nm colloid was administered subdermally in an injection volume of 0.4 ml. Blue dye mapping was successful in 30 of 40 patients (75%). In 26 of these patients, the dye and lymphoscintigraphy identified the same node; in 4 cases different nodes were identified. None of these four patients had axillary disease. CONCLUSION: Lymphoscintigraphy is a simple procedure that is well tolerated by patients. Sentinel node identification is more reliable when large-size radiolabeled colloids are injected in a relatively small injection volume (0.4 ml). Use of a GDP greatly facilitates precise pinpointing and rapid removal of the SN. 相似文献
93.
This study compared methadone maintenance patients with and without pathological gambling (n = 167). Participants completed a self-report survey assessing lifetime pathological gambling and past-2-month gambling behavior, and they completed the SF-12v2 Health Survey (J. E. Ware, M. Kosinski, & S. D. Keller, 1996), a measure of current mental and physical health. In the sample, 52.7% were classified as lifetime pathological gamblers, and the majority of pathological gamblers were actively gambling within the past 2 months. Multivariate analysis of covariance revealed that methadone maintenance patients with pathological gambling had significantly poorer mental and physical health than methadone maintenance patients without pathological gambling. These results suggest that pathological gamblers receiving methadone maintenance may benefit from additional psychosocial services. In fact, most pathological gamblers in the sample expressed interest in gambling-related services. These results extend previous research in other populations that has found that pathological gamblers report poorer mental and physical health than nonpathological gamblers. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
94.
High mechanical performance of fibre reinforced cementitious composites: the role of “casting-flow induced” fibre orientation 总被引:2,自引:2,他引:0
Governing the dispersion and the orientation of fibres in concrete through a suitably balanced set of fresh state properties
and a carefully designed casting procedure, is a feasible and cost-effective way to achieve a superior mechanical performance
of fibre reinforced cementitious composites, which may be required by the intended application, even keeping the fibre content
at relatively low values (e.g. around 1% by volume). In this paper the possibility of pursuing the above said “integrated”
approach has been addressed in the framework of larger project focused on developing a deflection-hardening FRCC (DHFRCC),
reinforced with 100 kg/m3 (1.27% by volume) of short steel fibres (13 mm long and 0.16 mm in diameter). The material has to be employed to manufacture
thin (30 mm) roof elements, without any kind of conventional reinforcement, which have been anticipated to work, as simply
supported beams, over a 2.5 m span. The study hence paves the way to the possibility of exploiting at an industrial level
the correlation among fresh state performance, fibre dispersion and hardened state properties of self consolidating steel
fibre reinforced concrete to achieve enhanced structural performance tailored to the specific application. 相似文献
95.
Pant D Reynolds LP Luther JS Borowicz PP Stenbak TM Bilski JJ Weigl RM Lopes F Petry K Johnson ML Redmer DA Grazul-Bilska AT 《Reproduction (Cambridge, England)》2005,129(2):191-200
To evaluate the effects of FSH, LH and/or cAMP on expression of connexin 43 (Cx43) in the ovine cumulus-oocyte complex (COC) and gap junctional intercellular communication (GJIC) of cumulus cells, two experiments were carried out. In experiment 1, Cx43 was immunodetected in the COC, before or after maturation, obtained from non-treated or FSH-treated ewes. The expression of Cx43 in the COC was greater (P < 0.01) on day 16 than on day 15 of the estrous cycle. In vivo FSH treatment decreased (P < 0.02) Cx43 expression on day 16 but not on day 15 of the estrous cycle. In experiment 2, intact COCs or isolated cumulus cells obtained from small and large follicles from FSH-treated ewes were cultured with or without FSH, LH or cAMP agonist and evaluated for GJIC by laser cytometry. For large follicles, the basal rate of GJIC was greater (P < 0.01) for cumulus cells in intact COCs than for isolated cumulus cells. FSH increased (P < 0.04) GJIC in cumulus cells in intact COCs and tended to increase (P < 0.1) GJIC in isolated cumulus cells from small follicles but decreased (P < 0.01) GJIC in cumulus cells in intact COCs from large follicles. LH also increased (P < 0.01) GJIC in isolated cumulus cells from small follicles but decreased GJIC in intact COCs (P < 0.01) and isolated cumulus cells (P < 0.02) from large follicles. cAMP increased (P < 0.01) the GJIC in both intact COCs and cumulus cells from small and large follicles. These results indicate that day of estrous cycle, stage of maturation and duration of FSH treatment affect expression of Cx43 in ovine COCs. In intact COCs, GJIC in cumulus cells was enhanced, probably due to the presence of the oocyte. In addition, the effects of FSH and LH, but not cAMP, on GJIC of cumulus cells depended on the stage of follicular development and on the presence of the oocyte. 相似文献
96.
Fischer A Seitz T Lochner A Sterner R Merkl R Bocola M 《Chembiochem : a European journal of chemical biology》2011,12(10):1544-1550
We present a computational saturation mutagenesis protocol (CoSM) that predicts the impact on stability of all possible amino acid substitutions for a given site at an internal protein interface. CoSM is an efficient algorithm that uses a combination of rotamer libraries, side-chain flips, energy minimization, and molecular dynamics equilibration. Because CoSM considers full side-chain and backbone flexibility in the local environment of the mutated position, amino acids larger than the wild-type residue are also modeled in a proper manner. To assess the performance of CoSM, the effect of point mutations on the stability of an artificial (βα)(8)-barrel protein that has been designed from identical (βα)(4)-half barrels, was studied. In this protein, position 234(N) is a previously identified stability hot-spot that is located at the interface of the two half barrels. By using CoSM, changes in protein stability were predicted for all possible single point mutations replacing wild-type Val234(N). In parallel, the stabilities of 14 representative mutants covering all amino acid classes were experimentally determined. A linear correlation of computationally and experimentally determined energy values yielded an R(2) value of 0.90, which is statistically significant. This degree of coherence is stronger than the ones we obtained for established computational methods of mutational analysis. 相似文献
97.
Petry Nancy M.; Weinstock Jeremiah; Alessi Sheila M. 《Canadian Metallurgical Quarterly》2011,79(5):686
Objective: Contingency management (CM) is efficacious in reducing drug use. Typically, reinforcers are provided on an individual basis to patients for submitting drug-negative samples. However, most treatment is provided in a group context, and poor attendance is a substantial concern. This study evaluated whether adding CM to group-based outpatient treatment would increase attendance and drug abstinence relative to standard care. Method: Substance abusing patients (N = 239) initiating outpatient treatment at 2 community-based clinics were randomized to standard care with frequent urine sample monitoring for 12 weeks (SC) or that same treatment with CM delivered in the context of group counseling sessions. In the CM condition, patients earned opportunities to put their names in a hat based on attendance and submission of drug-negative samples. At group counseling sessions, therapists selected names randomly from the hat, and individuals whose names were drawn won prizes ranging from $1 to $100. Results: Patients assigned to CM earned a median of $160 in prizes, and they attended significantly more days of treatment (d = 0.25), remained in treatment for more continuous weeks (d = 0.40), and achieved longer durations of drug abstinence (d = 0.26) than patients randomized to SC. Group adherence and therapeutic alliance also improved with CM. In addition, HIV risk behaviors were significantly lower in CM relative to SC patients during early phases of treatment and at the 12-month follow-up. Conclusions: These data demonstrate that CM delivered in the context of outpatient group counseling can increase attendance and improve drug abstinence. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
98.
Homan KA Chen J Schiano A Mohamed M Willets KA Murugesan S Stevenson KJ Emelianov S 《Advanced functional materials》2011,21(9):1673-1680
Colloidal "silver stars" were synthesized upon poly(lactic-co-glycolic) acid nanosphere templates via a facile two-step silver reduction method. Myriad dendrimer-like Ag star morphologies were synthesized by varying the amount of poly(vinyl alcohol) and trisodium citrate used during silver reduction. Scanning electron microscopy studies revealed that star-shaped silver-polymer composites possessing nanoscopic, fractal morphologies with diameters ranging from 500 nm to 7 μm were produced. These composites have broad applications from antibacterial agents to catalysis; two such applications were tested here. Surface-enhanced Raman spectroscopy (SERS) studies showed multiple hot spots of SERS activity within a single star. Electrochemical catalysis experiments demonstrated the feasibility of using the silver stars instead of platinum for the oxygen reduction reaction in alkaline fuel cells. 相似文献
99.
Milliken Bruce; Joordens Steve; Merikle Philip M.; Seiffert Adriane E. 《Canadian Metallurgical Quarterly》1998,105(2):203
The notion that inhibitory processes play a critical role in selective attention has gained wide support. Much of this support derives from studies of negative priming. The authors note that the attribution of negative priming to an inhibitory mechanism of attention draws its support from a common assumption underlying priming procedures, together with the procedure that has been used to measure negative priming. The results from a series of experiments demonstrate that selection between 2 competing prime items is not required to observe negative priming. This result is demonstrated across several experiments in which participants named 1 of 2 items in a second display following presentation of a single-item prime. The implications of these results for existing theories of negative priming are discussed, and a theoretical framework for interpreting negative priming and several related phenomena is forwarded. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
100.
Substance use disorders and pathological gambling share similarities in terms of diagnostic criteria, epidemiology, and clinical course. However, relatively few studies have evaluated the efficacy of treatments for gambling disorders. As interest in pathological gambling grows, adaptation of effective treatments from the field of substance abuse may advance the study of treatment for pathological gambling. This article reviews the similarities and differences between pathological gambling and substance use disorders. It describes psychotherapeutic and pharmacological treatments for substance use disorders and their translation to pathological gambling. Future research should consider investigating the onset and course of pathological gambling within the context of other psychiatric disorders, biological abnormalities associated with gambling, and combined effects of psychotherapy and pharmacotherapy in the treatment of this disorder. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献