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101.
TG Evans W Bonnez HR Soucier T Fitzgerald DC Gibbons RC Reichman 《Canadian Metallurgical Quarterly》1998,39(3):163-173
Criteria for detection of chromosome aberrations by Comparative Genomic Hybridization (CGH) are not standardized and improvement of this part of the analysis is of paramount importance to the applicability of the technique. The aim of this work was to suggest CGH detection criteria that increase the specificity and sensitivity and at the same time include chromosome regions previously excluded from CGH analysis. We analyzed 33 hybridizations with normal DNA and modified our CGH software in order to use a selection of these normal analyses as a model for interpretation of analyses of unknown samples. This approach was successfully tested on 14 samples with known aberrations. 相似文献
102.
The Kjeldahl and Dumas (combustion) methods were compared in 11 laboratories analyzing samples of milk, skim milk powder, whole milk powder, whey protein concentrate, infant formula, casein, caseinate, 2 reference compounds (glycine and EDTA), and a secondary reference skim milk powder. The comparison was conducted by using international standards where applicable. Overall means were 8.818 g N/100 g by the Kjeldahl method and 8.810 g N/100 g by the Dumas method. No evidence was found for a consistent bias between methods that may be of concern in the trading of dairy produce. A review of more than 10 related trials revealed a lack of consensus in the bias between the 2 methods, suggesting that differences in methodology and sources of systematic error may be contributors. For samples containing > 2 g N/100 g, the Dumas relative repeatability and reproducibility standard deviations were consistently about 0.35 and 0.75%, respectively, whereas the corresponding Kjeldahl values declined generally with N content and were significantly larger. The Dumas precision characteristics may be due to the dominance of Leco analyzers in this trials, and in most other recent trials, rather than an inherent method attribute. Protein determination methods for dairy products need to be reviewed and updated. The Dumas method needs Codex Alimentarius status as a recognized test method. 相似文献
103.
Peroxisome proliferators are a diverse group of chemicals that include several therapeutically used drugs (e.g., hypolipidemic agents), plasticizers and organic solvents used in the chemical industry, herbicides, and naturally occurring hormones. As the name implies, peroxisome proliferators cause an increase in the number and size of peroxisomes in the liver, kidney, and heart tissue of susceptible species, such as rats and mice. Long-term administration of peroxisome proliferators can cause liver cancer in these animals, a response that has been the central issue of research on peroxisome proliferators for many years. Peroxisome proliferators are representative of the class of nongenotoxic carcinogens that cause cancer through mechanisms that do not involve direct DNA damage. The fact that humans are frequently exposed to these agents makes them of particular concern to government regulatory agencies responsible for assuring human safety. Whether frequent exposure to peroxisome proliferators represents a hazard to humans is unknown; however, increased cancer risk has not been shown to be associated with long-term therapeutic administration of the hypolipidemic drugs gemfibrozil, fenofibrate, and clofibrate. To make sound judgments regarding the safety of peroxisome proliferators, the validity of extrapolating results from rodent bioassays to humans must be based on the agents' mechanism of action and species differences in biologic activity and carcinogenicity. The peroxisome proliferator-activated receptor alpha (PPARalpha), a member of the nuclear receptor superfamily, has been found to mediate the activity of peroxisome proliferators in mice. Gene-knockout mice lacking PPARalpha are refractory to peroxisome proliferation and peroxisome proliferator-induced changes in gene expression. Furthermore, PPARalpha-null mice are resistant to hepatocarcinogenesis when fed a diet containing a potent nongenotoxic carcinogen WY-14,643. Recent studies have revealed that humans have considerably lower levels of PPARalpha in liver than rodents, and this difference may, in part, explain the species differences in the carcinogenic response to peroxisome proliferators. 相似文献
104.
CR Dudley B Keavney IM Stratton RC Turner PJ Ratcliffe 《Canadian Metallurgical Quarterly》1995,48(6):1907-1911
We performed a case-control study to determine whether molecular variants of genes of the renin-angiotensin system were associated with the presence of albuminuria in non-insulin dependent diabetes mellitus (NIDDM). A total of 180 diabetic patients with persistent microalbuminuria [median urinary albumin (interquartile range) of 74 (54 to 126 mg/liter)] were matched with two control groups of diabetic patients without microalbuminuria [median urinary albumin 7 (5 to 10) mg/liter] for variables known to be associated with raised urinary albumin concentration including hemoglobin A1c and triglyceride. One control group was also matched for blood pressure and the other group was not, to allow assessment of interactions with hypertension. Association with the I/D polymorphism of the ACE gene and M235T variant of the angiotensinogen gene (AGT) with microalbuminuria and retinopathy was examined. There were no significant differences in genotype frequency between cases and controls for ACE or AGT irrespective of blood pressure matching. However, among subjects with microalbuminuria, those with the ACE DD genotype had a significantly greater urinary albumin excretion than individuals with a non-DD genotype [median 88 (68 to 170) mg/liter vs. 67 (53 to 113) mg/liter, P < 0.001]. More subjects with the DD than non-DD genotype had persistent albuminuria > 100 mg/liter, twice the upper normal range (60% vs. 38%, P = 0.006). When increased albumin excretion occurs, the presence of the ACE DD genotype appears to be associated with higher urinary albumin levels. No association with retinopathy was observed. 相似文献
105.
EK Runge RC Albers NE Christensen GE Zwicknagl 《Canadian Metallurgical Quarterly》1995,51(16):10375-10385
106.
107.
Wang Fei Zhang Weiwei Xu Zongfeng Ping Jingyu Chu Hao 《Neural computing & applications》2021,33(15):9061-9073
Neural Computing and Applications - In real-world application of affective brain–computer interface (aBCI), individual differences across subjects and non-stationary characteristics of... 相似文献
108.
针对空天飞行器再入段环境变化剧烈、气动参数变化范围大的特点,采用参数空间方法来设计其控制系统;首先建立飞行器控制系统的数学模型,鉴于飞行器再入过程中对攻角有着严格的要求,设计了以攻角反馈为被控信号的三回路自动驾驶仪结构,然后根据参数空间方法求出对应的控制器参数,最后基于Matlab/Simulink的非线性仿真表明,所设计的控制系统在大气密度偏差±30%、气动力/力矩系数各偏差±20%的组合偏差情况下仍具有较好的鲁棒稳定性和跟踪性能。 相似文献
109.
This paper is concerned with the problem of stochastic stability analysis for a class of genetic regulatory networks with Markovian jump parameters and time‐varying delays. A delay‐dependent stability criterion is derived by using a novel mode‐dependent Lyapunov functional. The derived stability criterion is expressed in terms of linear matrix inequalities and is less conservative than the existing ones in the literature. A numerical example is provided to demonstrate the effectiveness of the proposed stability criterion. Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society 相似文献
110.