全文获取类型
收费全文 | 1489篇 |
免费 | 2篇 |
专业分类
电工技术 | 4篇 |
综合类 | 1篇 |
化学工业 | 26篇 |
金属工艺 | 13篇 |
机械仪表 | 8篇 |
建筑科学 | 12篇 |
能源动力 | 7篇 |
轻工业 | 29篇 |
水利工程 | 5篇 |
无线电 | 9篇 |
一般工业技术 | 28篇 |
冶金工业 | 1317篇 |
原子能技术 | 2篇 |
自动化技术 | 30篇 |
出版年
2022年 | 4篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2018年 | 4篇 |
2017年 | 4篇 |
2016年 | 3篇 |
2015年 | 3篇 |
2014年 | 3篇 |
2013年 | 8篇 |
2012年 | 6篇 |
2011年 | 7篇 |
2010年 | 8篇 |
2009年 | 6篇 |
2008年 | 4篇 |
2007年 | 2篇 |
2006年 | 8篇 |
2005年 | 5篇 |
2004年 | 10篇 |
2003年 | 8篇 |
2002年 | 5篇 |
2001年 | 7篇 |
2000年 | 6篇 |
1999年 | 49篇 |
1998年 | 429篇 |
1997年 | 217篇 |
1996年 | 165篇 |
1995年 | 79篇 |
1994年 | 53篇 |
1993年 | 63篇 |
1992年 | 15篇 |
1991年 | 21篇 |
1990年 | 12篇 |
1989年 | 17篇 |
1988年 | 15篇 |
1987年 | 14篇 |
1986年 | 9篇 |
1985年 | 9篇 |
1984年 | 4篇 |
1983年 | 7篇 |
1982年 | 7篇 |
1981年 | 12篇 |
1980年 | 11篇 |
1978年 | 8篇 |
1977年 | 35篇 |
1976年 | 112篇 |
1975年 | 6篇 |
1973年 | 2篇 |
1971年 | 2篇 |
1966年 | 2篇 |
1955年 | 2篇 |
排序方式: 共有1491条查询结果,搜索用时 15 毫秒
1.
2.
JF DeFrance S Sands FC Schweitzer L Ginsberg JC Sharma 《Canadian Metallurgical Quarterly》1997,9(4):283-293
The purpose of this article is to deliberate the moral and legal dilemma entailed in the weapon of the labour strike as a pressure tactic on the Israeli Finance Ministry regarding job slots, budgets and, in effect, violating the collective agreement signed by the nurses and impairing patients' treatment, as opposed to refraining from striking and suffering the heavy burden of work, the lack of trained personnel, low wages, and the inability to give patients proper, high quality treatment. 相似文献
3.
Interleukin-2 (IL-2) therapy often causes gastrointestinal side effects and at least 8 cases of bowel perforation have been reported. The patient reported here developed a colosplenic fistula, diagnosed by CT, with no neoplastic involvement of these organs. Awareness of these complications of IL-2 can help lead to earlier diagnosis. 相似文献
4.
GB Lipford T Sparwasser M Bauer S Zimmermann ES Koch K Heeg H Wagner 《Canadian Metallurgical Quarterly》1997,27(12):3420-3426
Certain bacterial immunostimulatory (i.s.) DNA sequences containing unmethylated CpG motifs stimulate antigen-presenting cells (APC) to express a full complement of costimulatory molecules and to produce cytokines including interleukin (IL)-12 and tumor necrosis factor (TNF)-alpha. While IL-12 is key to their T helper cell (Th)1-promoting adjuvant activity, secretion of toxic levels of TNF-alpha is harmful in that it promotes toxic shock. Given the beneficial as well as harmful consequences of i.s. DNA, we investigated the possibility of identifying DNA sequences, i.e. CpG oligodeoxynucleotides (ODN) which differentially activate IL-12 versus TNF-alpha cytokine production in APC. Here, we describe an i.s. DNA sequence with these characteristics. While its potential to induce IL-12 is preserved, its ability to trigger TNF-alpha release is strongly curtailed both in vitro and in vivo. I.s. DNA could be segregated into lethal and non-lethal in a mouse toxic shock model. The non-toxic i.s. DNA was useful as an adjuvant, thus allowing cytotoxic T cell responses to the soluble protein ovalbumin and conferring a resistant Th 1 phenotype to BALB/c mice lethally infected with Leishmania major. This i.s. CpG motif may thus be prototypic for a useful immunostimulating DNA sequence that lacks harmful side effects. 相似文献
5.
The seeds of Crepis capillaris were used to examine the mutagenic und antimutagenic properties of human whole blood, plasma, serum albumin and gamma-globulin by recording chromosomal and chromatid aberrations. The antimutagenic activity was determined by preliminary, simultaneous, and subsequent biosubstrate treatments of the seeds. The whole and twice-diluted blood, as well as plasma, induced aberrations exceeding the level of self-arbitrary mutagenesis by 3.7-5.3 and 2.6-3.1 times, respectively. When the blood was diluted to its 20% concentration, the antimutagenic efficiency of biological fluids was recorded. Human serum albumin and gamma-globulin were found to have an antimutagenic effect. In the dilutions having no antimutagenic effect, blood, plasma, and albumin showed their ability to be effectively decrease the level of induced aberrations. 相似文献
6.
ES Buescher SM McIlheran SM Banks S Vadhan-Raj 《Canadian Metallurgical Quarterly》1993,21(11):1467-1472
During a phase I trial of the genetically engineered hematopoietic growth factor PIXY321 (granulocyte-macrophage colony-stimulating factor/interleukin-3 [IL-3] fusion protein), we examined the effects of PIXY321 treatment on human polymorphonuclear leukocyte (PMN) locomotive, respiratory burst, and phagocytic responses. PIXY321 treatment was associated with transient suppression of both unstimulated locomotion and chemotaxis responses to multiple stimuli, as well as significant transient enhancement of formyl peptide-stimulated H2O2 production. No effects on opsonic phagocytosis of Staphylococcus aureus were observed. In vitro exposure of control PMN to PIXY321 resulted in suppression of unstimulated locomotion/chemotaxis and enhancement of formyl peptide-stimulated H2O2 production but had no effects on phagocytosis. When patient cells were exposed in vitro to PIXY321 during treatment, suppression of chemotaxis and enhancement of H2O2 production were observed before PIXY321 treatment, but these effects diminished during treatment. The in vivo and in vitro exposure effects of PIXY321 treatment on PMN function are similar to those of the parent molecule, granulocyte-macrophage colony-stimulating factor (GM-CSF). 相似文献
7.
ES Lie A Heyden MK Johannesen M Boysen P Brandtzaeg 《Canadian Metallurgical Quarterly》1996,116(4):627-632
The frequency of human papillomavirus (HPV) in laryngeal papillomas varies largely among different studies. DNA in situ hybridization (ISH) has been the most widely used method for detection of HPV. The aim of this study was to compare the reproducibility and sensitivity of ISH with polymerase chain reaction (PCR) in 35 specimens of laryngeal papillomas routinely fixed in buffered or unbuffered formalin. Out of 12 specimens fixed in buffered formalin, 10 were positive for HPV 6/11 using ISH. The procedure was repeated three times and three specimens were positive only twice. Nine biopsies were positive for HPV using PCR with consensus primers (My 09/11) on dewaxed tissue without extracting DNA. In three repeated PCRs, the results were inconsistent in three samples. After DNA extraction, all 12 samples were positive with PCR. Of the 23 specimens fixed in unbuffered formalin, 14 were HPV-positive with ISH, while only one was positive with PCR. We concluded that PCR with My 09/11 consensus primers is a highly sensitive method for detection of HPV in laryngeal papillomas fixed in buffered formalin, but useless for samples fixed in unbuffered formalin. When DNA was extracted from the former type of fixed tissue, the results were highly reproducible. In contrast to PCR, ISH appeared to be less influenced by fixation procedure, but it was not as reproducible and sensitive as PCR. Negative results did not necessarily mean absence of HPV. 相似文献
8.
STUDY DESIGN: This study retrospectively reviewed the intermediate-term clinical outcome of patients who were 50 years of age or older at the time they experienced their cervical spinal cord injury. OBJECTIVES: To establish reasonable expectations for the functional outcome in the older patient with cervical spinal cord injury. BACKGROUND DATA: The long-term morbidity and mortality of large groups of patients with spinal cord injury have been reported. The specific functional ability, disposition, morbidity, and mortality of this group of older patients injured after 50 years of age, however, have been less well defined. METHODS: Forty-one consecutive patients older than 50 years of age at the time of cervical cord injury were studied, and functional abilities, independence, need for assistance in activities of daily living, disposition, morbidity, and mortality were assessed. All patients had more than 2 years of follow-up examinations (mean, 5.5 years) by the same spine injury service. RESULTS: There were 13 complete and 28 incomplete cervical cord lesions. The mean age of the patients at follow-up examination was 67.5 years. The average follow-up period was 5.5 years after injury. None of the patients with complete cord injury improved, and all required extensive care. Twenty-one (80%) of 26 of the patients with incomplete cord injury were able to ambulate with some assistance. Nineteen of 26 patients had independent or near-independent abilities with activities of daily living. Twenty (77%) of 26 were able to return home. All patients with complete cord injury (13 of 13) had died by the time of the follow-up visit. Seventy-seven percent (10 of 13) of this patient group had died within the first year. Those surviving lived an average of 3.5 years after their injury. Fourteen of 28 patients with incomplete cord injury (50%) had died by the time of the follow-up visit. Six (43%) of the 14 deaths were attributed to complications of their spinal cord injury. CONCLUSION: The functional outcome of the person older than 50 years with a complete cervical cord injury is poor. Of the 14% who survived the first year, all required extensive attendant care, and no neurologic improvement was seen. The patient with an incomplete cord injury has an overall good outcome regarding ambulation and returning to home. 相似文献
9.
This report analyzes the intracorporal lengths of 236 consecutive organically impotent men who underwent insertion of a penile prosthesis. The average right or left intracorporal length in this series was 20.9 cm, with a standard deviation of 2.2 cm. Intracorporal length ranged from 14-27 cm. This data may be used as reference ranges for penile prosthesis manufacturers, and for Urologists who implant prostheses or perform penile lengthening procedures. 相似文献
10.
Continuous monitoring of submillisecond free-solution dynamics of individual rhodamine-6G molecules and 30-base single-stranded DNA tagged with rhodamine was achieved. Fluorescence images were recorded from the same set of isolated molecules excited either through the evanescent field at the quartz-liquid interface or as a thin layer of solution defined by micron-sized wires, giving diffraction-limited resolution of inter-connected attoliter volume elements. The single-molecule diffusion coefficients were smaller and the unimolecular photodecomposition lifetimes were longer for the dye-DNA covalent complex as compared with those of the dye molecule itself. Unlike bulk studies, stochastic behavior was found for individual molecules of each type, and smaller diffusion coefficients were observed. 相似文献