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31.
Amines such as dopamine, norepinephrine and epinephrine were analysed in the brain regions of O.mossambicus exposed to quinalphos, phenthoate and their combination for 96 hr. The three types of treatments significantly (P < 0.05) altered the amines level at various intervals in the brain regions.  相似文献   
32.
Brucella abortus strain RB51 was recently approved as an official brucellosis calfhood vaccine for cattle by the Animal and Plant Health Inspection Service branch of the United States Department of Agriculture. Currently available serologic surveillance tests for B. abortus do not detect seroconversion following SRB51 vaccination. The purpose of this study was to evaluate a dot-blot assay using gamma-irradiated strain RB51 bacteria for its specificity and sensitivity to detect antibody responses of cattle vaccinated with strain RB51. Dot-blot titers of sera at a recommended dosage (10(10) colony-forming units) were similar to those of sera from cattle vaccinated with similar numbers of B. abortus strain 19 and greater (P < 0.05) than titers of nonvaccinated cattle. In the first 12 weeks after vaccination with 10(10) colony-forming units of strain RB51, the RB51 dot-blot assay had 100% specificity for titers of 80 or less and a 53% sensitivity for titers of 160 or greater. Sensitivity of the RB51 dot-blot assay peaked at 4 weeks after vaccination with 10(10) colony-forming units of strain RB51. Dot-blot responses of sera from cattle vaccinated with a reduced dosage of strain RB51 (10(9) colony-forming units) did not differ (P > 0.05) from titers of sera from nonvaccinated cattle. Following intraconjunctival challenge with B. abortus strain 2308, titers on the RB51 dot-blot assay did not differ (P > 0.05) between nonvaccinated cattle and cattle vaccinated at calfhood with strain 19 or strain RB51.  相似文献   
33.
The effects of azadirachtin, salannin, nimbin, and 6-desacetylnimbin on ecdysone 20-monooxygenase (E-20-M) activity were examined in three insect species. Homogenates of wandering stage third instar larvae of Drosophila melanogaster, or abdomens from adult female Aedes aegypti, or fat body or midgut from fifth instar larvae of Manduca sexta were incubated with radiolabeled ecdysone and increasing concentrations (from 1 x 10(-8) to 1 x 10(-3) M) of the four compounds isolated from seed kernels of the neem tree, Azadirachta indica. All four neem tree compounds were found to inhibit, in a dose-dependent fashion, the E-20-M activity in three insect species. The concentration of these compounds required to elicit a 50% inhibition of this steroid hydroxylase activity in the three insect species examined ranged from approximately 2 x 10(-5) to 1 x 10(-3).  相似文献   
34.
This paper describes an efficient technique for the design of fault-secure VLSI circuits based on differential cascode voltage switch (DCVS) logic. We propose a new synthesis method for constructing DCVS circuits with a near-optimal transistor count based on binary decision diagrams (BDDs). the time and memory resources required are very low, making the technique practical even for PC-based synthesis tools. This method is the basis for a CAD tool that allows automatic synthesis of fault-secure circuits based on the DCVS technology. We finally present an improved design and implementation of a 2's complement serial/parallel multiplier as an application of the proposed technique and algorithm.  相似文献   
35.
Vibrio cholerae causes epidemic diarrhea throughout the world. Fluid replacement is the primary therapy for cholera; however, high mortality rates often necessitate the use of antibiotics. V. cholerae, like most bacteria, has developed resistance to some antibiotics. In the early 1990s a new serotype strain, Bengal 0139, began a new wave of cholera epidemics. Bengal isolates showed unique trends in antimicrobial resistance. Many clinical laboratories use automated antibiotic susceptibility testing for V. cholerae. It is important to know if automated susceptibility test results for V. cholerae coincide with reported trends in antibiotic susceptibility. In the present study, we used the Vitek automated susceptibility system to determine the susceptibilities of 79 V. cholerae O1 isolates, 100 O139 isolates, and 112 non-O1 isolates. Vitek susceptibilities for V. cholerae showed a good correlation with preestablished epidemiological data. Although the new O139 serogroup showed a trend of increased resistance to trimethoprim-sulfamethoxazole and nitrofurantoin, it was more susceptible to ampicillin than previous serogroup O1 and non-O1 strains. Regardless of serogroup, > or = 98% of the V. cholerae isolates tested were susceptible to most antibiotics tested by us. It is important to continue susceptibility testing of all new isolates of V. cholerae because of emerging resistant strains. However, V. cholerae remains susceptible to most of the available antibiotics.  相似文献   
36.
Electrical time-to-breakdown (TTB) measurements have shown the charge to breakdown Qbd of gate oxide capacitors fabricated on n-type well (n-well) substrates always to be higher than that of capacitors on p-type well (p-well) substrates on the same wafer when both are biased into accumulation under normal test conditions. Here the authors correlate the higher n-well Qbd to smooth capacitor oxide/substrate interfaces and minimized grain boundary cusps at the poly-Si gate/oxide interfaces, confirming that Fowler-Nordheim tunneling is the dominant current conduction mechanisms through the oxide. They correlate higher Qbd to higher barrier height for a given substrate type and observe that the slope of the barrier height versus temperature plot is lower for both p-well and n-well cases with electrons tunneling from the silicon substrate. This is attributed to surface roughness at the poly-Si gate/SiO2 interface. A poly-Si gate deposition and annealing process with clean, smooth oxide/substrate interfaces will improve the p-well breakdown characteristics and allow higher Qbd to be achieved  相似文献   
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Two purified animal venom toxins, crotoxin and cardiotoxin, have been combined to produce a unique natural product (VRCTC-310) currently under investigation as an antitumor agent by the National Cancer Institute. In vitro, it has demonstrated cytotoxic disease specificity and a unique mechanism of action when submitted to COMPARE analysis. In vivo, tolerance was developed to the neurotoxic properties of crotoxin which allowed comparison of several schedules of fixed and escalating daily i.m. doses to mice bearing s.c. Lewis Lung carcinoma. An 83% inhibition of tumor growth was achieved using an escalating dose schedule starting at 1.8 mg/kg and reaching 6.3 mg/kg/day on day 20. Although some irritation around the sites of i.m. injection was noted, animal weight loss was negligible and there were no other signs of adverse toxicity. This natural product represents a new, membrane interactive anticancer agent which produces a unique spectrum of cytotoxicity in vitro and which has demonstrated interesting in vivo antitumor efficacy.  相似文献   
40.
We compared the data from four growth hormone (GH) immunoassays for analyzing 24-h GH profiles in four apparently normal subjects and four obese subjects (508 serum samples). The detection limit was 0.02 microgram/L for one immunochemiluminometric assay (ICMA), 0.1 microgram/L for two IRMAs, and 0.4 microgram/L for one RIA. All GH pulses with a peak ICMA value > 1 microgram/L were detected by each of the other methods. Overall, the correlation coefficient between the values obtained with all four assays exceeded 0.90. However, for GH concentrations < or = 0.25 microgram/L, acceptable concordance (r2 > or = 0.80) was reached only between the ICMA and one IRMA; between the ICMA and the RIA, concordance was acceptable only for GH concentrations > or = 10 micrograms/L. In the normal subjects, the percentage of undetectable values was 0% with the ICMA but 29% with one of the IRMAs; in obese subjects, the corresponding values were 12% and 38%.  相似文献   
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