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排序方式: 共有1183条查询结果,搜索用时 15 毫秒
911.
This article proposes a graph-theoretic methodology for query approximation in Geographic Information Systems, enabling the
relaxation of three kinds of query constraints: topological, semantic and structural. An approximate query is associated with
a value corresponding to the degree of similarity with the original query. Such a value is computed for topological constraints
on the basis of the topological distance between configurations, for semantic constraints using the information content approach,
and for structural constraints revisiting the maximum weighted matching problem in bipartite graphs. Finally, the high correlation
of our proposal with human judgment is demonstrated by an experiment. 相似文献
912.
AT Hatjimihail 《Canadian Metallurgical Quarterly》1993,39(9):1972-1978
In general, one cannot use algebraic or enumerative methods to optimize a quality-control (QC) procedure for detecting the total allowable analytical error with a stated probability with the minimum probability for false rejection. Genetic algorithms (GAs) offer an alternative, as they do not require knowledge of the objective function to be optimized and can search through large parameter spaces quickly. To explore the application of GAs in statistical QC, I developed two interactive computer programs based on the deterministic crowding genetic algorithm. Given an analytical process, the program "Optimize" optimizes a user-defined QC procedure, whereas the program "Design" designs a novel optimized QC procedure. The programs search through the parameter space and find the optimal or near-optimal solution. The possible solutions of the optimization problem are evaluated with computer simulation. 相似文献
913.
This project was undertaken to study the survival properties of various prostate cells, including normal (NHP), BPH (benign prostate hyperplasia), primary carcinoma (PCA), and metastatic prostate cancer cells (LNCaP, PC3, and Du145), in the absence of trophic factors. Cell proliferation and cell death were quantitated by enumerating the number of live cells using MTS/PMS kit and of dead (apoptotic) cells using 4',6-diamidino-2-phenylindole dihydrochloride nuclear staining. These cells demonstrated an overall survivability in the order of BPH < NHP < LNCaP < PC3 < PCA < Du145. Upon growth factor deprivation, NHP/BPH cells rapidly underwent apoptosis, leading to a decreased number of live cells. PCA/PC3/Du145 cells, in contrast, demonstrated an initial phase of aggressive growth during which apoptosis rarely occurred, followed by a "plateau" phase in which cell loss by apoptosis was compensated by cell proliferation, followed by a later phase in which apoptosis exceeded the cell proliferation. LNCaP cells demonstrated survival characteristics between those of NHP/BPH and PCA/PC3/Du145 cells. We concluded that the increased survivability in prostate cancer cells results from enhanced cell proliferation as well as decreased apoptosis. The molecular mechanisms for evasion of apoptosis in prostate cancer cells were subsequently investigated. Quantitative Western blotting was used to examine the protein expression of P53 and P21WAF-1, Bcl-2 and Bcl-X(L) (anti-apoptotic proteins), and Bax, Bak, and Bad (proapoptotic proteins). The results revealed that, upon trophic factor withdrawal, NHP and BPH cells upregulated wild-type p53 and proapoptotic proteins Bax/Bad/Bak and down-regulated the expression of P21. Furthermore, NHP and BPH cells endogenously expressed little or no Bcl-2. In sharp contrast, prostate cancer cells expressed nonfunctional P53 and various amounts of Bcl-2 proteins. Upon deprivation, these cancer cells up-regulated P21 and Bcl-2 and/or BclX(L), lost response to withdrawal-induced up-regulation of Bax/Bad/Bak or decreased or even completely lost Bax expression and expressed some novel proteins such as P25 and P54/55 complex. These data together suggest that prostate cancer cells may use multiple molecular mechanisms to evade apoptosis, which, together with increased proliferation, contribute to extended survivability of prostate cancer cells in the absence trophic factors. 相似文献
914.
WT Sause C Scott S Taylor D Johnson R Livingston R Komaki B Emami WJ Curran RW Byhardt AT Turrisi 《Canadian Metallurgical Quarterly》1995,87(3):198-205
BACKGROUND: Regionally advanced, surgically unresectable non-small-cell lung cancer represents a disease with an extremely poor prognosis. External-beam irradiation to the primary tumor and regional lymphatics is generally accepted as standard therapy. The use of more aggressive radiation regimens and the addition of cytotoxic chemotherapy to radiotherapy have yielded conflicting results. Recently, however, results from clinical trials using innovative irradiation delivery techniques or chemotherapy before irradiation have indicated that patients treated with protocols that incorporate these modifications may have higher survival rates than patients receiving standard radiation therapy. PURPOSE: On the basis of these results, the Radiation Therapy Oncology Group (RTOG)-Eastern Cooperative Oncology Group (ECOG) elected to conduct a phase III trial comparing the following regimens: 1) standard radiation therapy, 2) induction chemotherapy followed by standard radiation therapy, and 3) twice-daily radiation therapy. METHODS: Patients with surgically unresectable stage II, IIIA, or IIIB non-small-cell lung cancer were potential candidates. Staging was nonsurgical. Patients were required to have a Karnofsky performance status of 70 or more and weight loss less than 5% for 3 months prior to entry into the trial, to be older than 18 years of age, and to have no metastatic disease. Of the 490 patients registered in the trial, 452 were eligible. The disease in 95% of the patients was stage IIIA or IIIB. More than two thirds of the patients had a Karnofsky performance status of more than 80. Patients were randomly assigned to receive either 60 Gy of radiation therapy delivered at 2 Gy per fraction, 5 days a week, over a 6-week period (standard radiation therapy); induction chemotherapy consisting of cisplatin (100 mg/m2) on days 1 and 29 and 5 mg/m2 vinblastine per week for 5 consecutive weeks beginning on day 1 with cisplatin, followed by standard radiation therapy starting on day 50; or 69.6 Gy delivered at 1.2 Gy per fraction twice daily (hyperfractionated radiation therapy). RESULTS: Toxicity was acceptable, with four treatment-related deaths. Three patients subsequently died of chronic pulmonary complications. Compliance with protocol treatment was acceptable. One-year survival (%) and median survival (months) were as follows: standard radiation therapy--46%, 11.4 months; chemotherapy plus radiotherapy--60%, 13.8 months; and hyperfractionated radiation therapy--51%, 12.3 months. The chemotherapy plus radiotherapy arm was statistically superior to the other two treatment arms (logrank P = .03). CONCLUSIONS: In "good-risk" patients with surgically unresectable non-small-cell lung cancer, induction chemotherapy followed by irradiation was superior to hyperfractionated radiation therapy or standard radiation therapy alone, yielding a statistically significant short-term survival advantage. 相似文献
915.
Leila Safari Erkan Yuce Shahram Minaei Giuseppe Ferri Vincenzo Stornelli 《International Journal of Circuit Theory and Applications》2020,48(7):1180-1193
In this paper, an implementation of a simulated grounded inductor (SGI) based on a recently developed active building block called second-generation voltage conveyor (VCII) is proposed. The proposed SGI employs two VCIIs, two resistors, and one grounded capacitor, which is preferred when integration is involved. More importantly, unlike most of the other previously reported SGIs, this one is free from any restrictive matching conditions. A complete analysis of nonidealities along with sensitivity treatment by considering parasitic impedances and nonideal gains of the VCII are performed. A simple VCII circuit is designed to be used in the implementation of the proposed SGI. To support the presented theory, Pspice simulation results using 0.18-μm CMOS technology parameters and supply voltage of ±0.9 V are provided. On the basis of the achieved results, the proposed SGI operates in a good agreement with an ideal inductor. The power consumption is only 0.65 mW, and the parasitic series impedance is approximately 191.9 Ω. The applicability of the proposed SGI is tested by using it in a standard second-order high-pass RLC filter. 相似文献
916.
Ivan Nastasijevic Francesco Proscia Marija Boskovic Milica Glisic Bojan Blagojevic Simona Sorgentone Andrej Kirbis Maurizio Ferri 《Journal of Food Safety》2020,40(5):e12819
Campylobacter is the most common cause of bacterial gastroenteritis worldwide and the most frequently reported foodborne pathogen in the European Union (EU). While campylobacteriosis is generally self-limiting, some patients could develop severe sequelae. The predominant source of infection is poultry. This review addresses the most relevant factors influencing the prevalence and contamination level of Campylobacter spp. in the poultry chain continuum. The emphasis was put on the novel control strategy for Campylobacter that is based on evidence-based risk assessment and the introduction of process hygiene criterion intended for monitoring the prevalence and counts of Campylobacter spp. on broiler carcasses at slaughter level. The reduction of Campylobacter spp. in the poultry meat chain in the EU can only be achieved with an integrated meat safety assurance approach. This includes primary interventions at the level of the poultry farm, implementation of effective control measures at slaughterhouses, and fostering awareness campaigns aimed at consumers. 相似文献
917.
918.
919.
C. Neri A. Coletti M. Ferri de Collibus G. Fornetti F. Pollastrone 《Fusion Engineering and Design》2009,84(2-6):224-228
A prototype of a laser in vessel viewing and ranging system was developed at ENEA laboratories in Frascati, it uses the amplitude modulated laser radar concept and it is conceived to withstand the severe ITER conditions. The in vessel viewing system (IVVS) probe has been designed and built to perform sub-millimetric three-dimensional images inside ITER; it is based on an intrinsically radiation resistant concept and architecture. A first characterization of the IVVS probe under room conditions was made at Frascati Labs on a full-scale mock-up of the ITER first wall panel (FWP) and of the divertor vertical target. The first characterization demonstrated that an upgrade of the IVVS performances was necessary especially to cope with divertor surfaces made of carbon material, which is highly absorbent from optical point of view.The paper describes the new developments of IVVS prototype to increase range measurement performances that was obtained increasing the modulation frequency, the optical efficiency of the probe optics and the laser power. A new test campaign has been carried out on the upgraded IVVS and a compact characteristic curve describing its performances has been found both in mathematical and graphical form. As far as viewing is concerned, the system has confirmed the sub-millimetric viewing resolution, reaching in the worst cases ~1 mm of resolution. The image quality was excellent in almost all the cases. The range measurement performance of IVVS system has been strongly upgraded reducing the standard deviation of range measure of a factor varying from 6 to 12. The increased performance allows measuring surface shapes and erosion on first wall tiles and divertor also for inclination angles completely outside the previous IVVS characteristics. 相似文献
920.
Federica Pizzo Zaira Maroccia Ivano Hammarberg Ferri Carla Fiorentini 《International journal of molecular sciences》2022,23(11)
The microbiota is increasingly recognized as a critical player in cancer onset and progression and response to cancer chemotherapy treatment. In recent years, several preclinical and clinical studies have evidenced the involvement of microbiota in lung cancer, one of the world’s deadliest cancers. However, the mechanisms by which the microbiota can impact this type of cancer and patient survival and response to treatments remain poorly investigated. In this review, the peculiarities of the gut and lung microbial ecosystems have been highlighted, and recent findings illustrating the possible mechanisms underlying the microbiota–lung cancer interaction and the host immune response have been discussed. In addition, the mucosal immune system has been identified as a crucial communication frame to ease interactive dynamics between the immune system and the microbiota. Finally, the use of specific next-generation intestinal probiotic strains in counteracting airway diseases has been evaluated. We believe that restoring homeostasis and the balance of bacterial microflora should become part of the routine of integrated cancer interventions, using probiotics, prebiotics, and postbiotics, and promoting a healthy diet and lifestyle. 相似文献