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971.
Although much is known about the characteristics of employees who smoke cigarettes, very little is known about workers who use smokeless tobacco. The current study was designed to understand the characteristics of smokeless tobacco users in relation to their performance at work and compare them with smokers and former tobacco users. Data were collected via interviews and questionnaires from a random sample of employees working at Pacific Lumber Company (N = 146), the largest single-site lumber mill in California. A total of 63 smokeless tobacco users (21 of whom also smoked cigarettes), 43 cigarette smokers, and 40 employees who had successfully quit using tobacco (34 of whom previously used cigarettes only) provided information about their health behavior, quality of work life, and performance at work. Analyses revealed that smokeless tobacco users reported less healthful sleep patterns, drank alcohol more often, were intoxicated more often, reported less job satisfaction and organizational commitment, and reported that both chewers and smokers do not work as hard and take more breaks than do tobacco-free employees (quitters). Specific differences among chewers-only, smokers-only, smokers-and-chewers, and quitters are presented. Results suggest the organizational value of developing worksite cessation programs for smokeless tobacco users.  相似文献   
972.
We present the first Fourier transform infrared (FTIR) analysis of an isotope-labeled eukaryotic membrane protein. A combination of isotope labeling and FTIR difference spectroscopy was used to investigate the possible involvement of tyrosines in the photoactivation of rhodopsin (Rho). Rho --> MII difference spectra were obtained at 10 degrees C for unlabeled recombinant Rho and isotope-labeled L-[ring-2H4]Tyr-Rho expressed in Spodoptera frugiperda cells grown on a stringent culture medium containing enriched L-[ring-2H4]Tyr and isolated using a His6 tag. A comparison of these difference spectra revealed reproducible changes in bands that correspond to tyrosine and tyrosinate vibrational modes. A similar pattern of tyrosine/tyrosinate bands has also been observed in the bR --> M transition in bacteriorhodopsin, although the sign of the bands is reversed. In bacteriorhodopsin, these bands were assigned to Tyr-185, which along with Pro-186 in the F-helix, may form a hinge that facilitates alpha-helix movement.  相似文献   
973.
LR7/8B is a member of the low density lipoprotein receptor gene family that is specifically synthesized in the brain. Here we have functionally expressed in 293 cells the splice variant harboring eight ligand binding repeats (LR8B). As assessed by confocal microscopy, the expressed receptor is localized to the plasma membrane. Importantly, in cell binding experiments, we demonstrate that this protein is a receptor for activated alpha2-macroglobulin. Because to date low density lipoprotein receptor-related protein (LRP) has been shown to be the only alpha2-macroglobulin receptor in brain, we became interested in the expression pattern of both proteins at the cellular level in the brain. LR7/8B is expressed in large neurons and Purkinje cells of the cerebellum and in cells constituting brain barrier systems such as the epithelial cells of the choroid plexus, the arachnoidea, and the endothelium of penetrating blood vessels. Anti-LR7/8B antibody stains the plasma membrane, dendrites, and vesicular structures close to the cell membrane of neurons, especially of Purkinje cells. In contrast, LRP is present in patchy regions around large neurons and most prominently in the glomeruli of the stratum granulare of the cerebellum. This suggests that, contrary to LR7/8B, LRP is expressed in synaptic regions of the neurons; furthermore, there is a striking difference in the expression patterns of LR7/8B and LRP in the choroid plexus. Whereas LRP shows baso-lateral and apical localization in the epithelial cells, LR7/8B is restricted to the apical cell aspect facing the cerebrospinal fluid. Finally, these studies were extended to cultured primary rat neurons, where double immunofluorescence labeling with anti-LR7/8B and anti-microtubuli-associated protein 2 (MAP2) confirmed the somatodendritic expression of the receptor. Based upon these data, we propose that LR7/8B is involved in the clearance of alpha2-macroglobulin.proteinase complexes and/or of other substrates bound to alpha2-macroglobulin from the cerebrospinal fluid and from the surface of neurons.  相似文献   
974.
Populus deltoides was treated with straight chain alcohols from methanol to n-hexanol, mono and triethanolamine, water, ethyleneglycol, acetone, cyclohexane and lactic acid. A batch reactor was used in all the runs and the temperature range used was from 100 to 320°C. A reaction ordinate concept was used to evaluate the treatment severities. The results of these experiments showed a significant influence of the solvent on the extent of liquefaction of wood as well as on the holocellulose and lignin contents of the residues. An attempt to relate the liquefaction profiles to the solubility parameters of the solvents is discussed.  相似文献   
975.
This paper examines the long-run relationship between the Shanghai index and CRB commodity index. We run our vector error correction model (VECM) for two sub-samples as pre-crisis period and post-crisis period. In pre-crisis period, there is strong bidirectional causality link between the Shanghai and CRB. In post-crisis period, there is no causality between the indices. In the second part of the article, we employ Fuzzy System Modeling (FSM) to increase the performances of root mean-square error, R2 and Adjusted R2. We show the results of our analysis for both Shanghai and CRB indexes. We have demonstrated the results for a good number of our investigations ANFIS, GENFIS, Classical LSE and three versions of support vector regression. For both Shanghai and CRB indexes, our FSMIFF with LSE obtains better results than all other models we have investigated and thus are more suitable for forecasting stable and unstable stock market behavior.  相似文献   
976.
977.
Vitreous carbon (VC), pyrolytic carbon (PC) and moulded graphite (MG) were tested as cathodic materials in hydrogen production by water electrolysis in the presence of the ionic liquid tetrafluoroborate of 3-triethylammonium-propane sulfonic acid (TEA-PS.BF4). The physical characterization of the carbon materials indicated large differences in the microstructure of VC, PC, and MG and this significantly affected their electrochemical response. The mechanism presented for all the materials studied in the hydrogen evolution reaction (HER) was Volmer–Heyrovsky, where the H2 desorption at the catalytic surface is the determining step. The MG electrode presented an unfavourable performance due to the formation of nanobubbles that coalesced without H2 desorption and led to the deactivation of the catalytic sites. This behaviour is attributed to the presence of large and ordered crystallites at the material surface, with a greater number of hydrophobic domains in comparison with VC and PC material surfaces. The VC and PC electrodes presented a higher performance compared to the Pt cathode, showing lower activation energy, higher cathodic exchange current and lower charge transfer resistance. The set of results indicates VC and PC as promising alternative materials to constitute cathodes for the electrolysis of water using TEA-PS.BF4 aqueous solution as electrolyte.  相似文献   
978.
More than 400 million people in the developing world depend on dryland agriculture for their livelihoods. Dryland agriculture involves a complex combination of productive components: staple crops, vegetables, livestock, trees and fish interacting principally with rangeland, cultivated areas and watercourses. Managing risk and enhancing productivity through diversification and sustainable intensification is critical to securing and improving rural livelihoods. The main biophysical constraints are natural resource limitations and degradation, particularly water scarcity and encroaching desertification. Social and economic limitations, such as poor access to markets and inputs, weak governance and lack of information about alternative production technologies also limit the options available to farmers. Past efforts to address these constraints by focusing on individual components have either not been successful or are now facing a declining rate of impact, indicating the need for new integrated approaches to research for development of dryland systems. This article outlines the characteristics of such an approach, integrating agro-ecosystem and livelihoods approaches and presents a range of empirical examples of its application in dryland contexts. The authors draw attention to new insights about the design of research required to accelerate impact by integrating across disciplines and scales.  相似文献   
979.
Two non‐GMO biofortified and one traditional pearl millet varieties were compared in abrasive decortication studies to evaluate their potential for increasing iron and zinc content. The phytate‐to‐mineral ratios were used to estimate mineral bioavailability. Iron and zinc contents in the biofortified varieties Tabi and GB8735 were two to threefold higher than in the traditional variety. Iron content reached 7.2 and 6.7 mg per 100 g DM in the biofortified varieties, which corresponds to the target values of biofortification programs. Zinc content was, respectively, 5.6 and 4.1 mg per 100 g DM in the GB8735 and Tabi varieties. Because of the presence of phytate and other chelating factors that were only partially removed during decortication, there was no improvement in iron bioavailability in the biofortified varieties. But whatever extraction rate, phytate‐to‐zinc ratios ranged between 6 and 18; zinc absorption could be improved by using these biofortified varieties for food processing.  相似文献   
980.
A rich (250 I (59 gal) per ton) Green River oil shale was retorted in a helium atmosphere. Isothermal retort experiments from 375 to 500 °C were carried out at 78 kPa and 765 kPa. Oil was collected as a function of time and a comprehensive analytical procedure was developed and utilized to determine seven oil fractions: straight-chain pentane de-asphaltened dry whole oil (DDWO); solids; saturates (S); aromatics (A); olefins (0); ‘weak’ polars (WP); and polars (P). The objectives of this work were: (a) to develop data to show oil generation and composition at different temperatures and pressures under isothermal, isobaric conditions; (b) to determine the effect of pressure on total oil yield and product-oil composition. Total oil yield was reduced as the pressure was increased. Much of this reduction can be accounted for in the reduced amounts of polar compounds formed at higher pressure because the polar fraction comprises approximately 35–45 wt% of the DDWO. In general, the amounts of aromatics present increase, the amounts of olefins decrease, and the amounts of saturates and ‘weak’ polar compounds remain relatively constant with increased system pressure.  相似文献   
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