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991.
On the basis of a monthly sampling effort from March 2005 to February 2006, the total concentrations of the sums of 27 and 15 polycyclic aromatic hydrocarbons (defined as sigma27PAHs and sigma15PAHs, respectively) in riverine runoff of the Pearl River Delta (PRD), China, and associated fluxes were determined. No clear temporal and spatial trends of PAH concentrations were found at all eight riverine runoff outlets where the samples were collected. The annual fluxes of sigma27PAHs and sigma15PAHs from the PRD to the coastal ocean were 60.2 and 33.9 metric tons, respectively. Assuming that riverine flux was positively related to the regional emission of PAHs, the annual riverine fluxes from five major rivers in China to the global oceans were estimated, which are quite significant relative to other major rivers of the world. On the basis of mass balance considerations, approximately 87% of sigma15PAHs inputting to the Pearl River Estuary and northern South China Sea was derived from riverine runoff from the PRD. In addition, approcimately 22.3 metric tons of sigma15PAHs annually outflow to open seas, which is equivalent to a concentration of 0.34 pg/L in the global oceans if the PAHs are evenly distributed in the upper 200 m of the water column. A comparison with the global background level of PAHs indicated that approximately 0.4% of PAHs in the open oceans may have been contributed by 1-year discharge from the PRD.  相似文献   
992.
Spherical silica particles containing nanoscale zerovalent iron were synthesized through an aerosol-assisted process. These particles are effective for groundwater remediation, with the environmentally benign silica particles serving as effective carriers for nanoiron transport. Incorporation of iron into porous sub-micrometer silica particles protects ferromagnetic iron nanoparticles from aggregation and may increase their subsurface mobility. Additionally, the presence of surface silanol groups on silica particles allows control of surface properties via silanol modification using organic functional groups. Aerosolized silica particles with functional alkyl moieties, such as ethyl groups on the surface, clearly adsorb solubilized trichloroethylene (TCE) in water. These materials may therefore act as adsorbents which have coupled reactivity characteristics. The nanoscale iron/silica composite particles with controlled surface properties have the potential to be efficiently applied for in situ source depletion and in the design of permeable reactive barriers.  相似文献   
993.
Compounds generated by the enzymatic hydrolysis of glucosinolates naturally present in mustard powder are potently bactericidal against Escherichia coli O157:H7. Because E. coli O157:H7 can survive the dry fermented sausage manufacturing process, 2, 4, and 6% (wt/wt) nondeheated (hot) mustard powder or 6% (wt/wt) deheated (cold) mustard powder were added to dry sausage batter inoculated with E. coli O157:H7 at about 7 log CFU/g to evaluate the antimicrobial effectiveness of the powders. Reductions in E. coli O157:H7 populations, changes in pH and water activity (aw), effects on starter culture (Pediococcus pentosaceus and Staphylococcus carnosus) populations, and effects of mustard powder on sausage texture (shear) were monitored during ripening. Nondeheated mustard powder at 2, 4, and 6% in dry sausage (0.90 aw) resulted in significant reductions in E. coli O157:H7 (P < 0.05) of 3.4, 4.4, and 6.9 log CFU/g, respectively, within 30 days of drying. During fermentation and drying, mustard powder did not affect P. pentosaceus and S. carnosus activity in any of the treatments. Extension of drying to 36 and 48 days reduced E. coli O157:H7 by >5 log CFU/g in the 4 and 2% mustard powder treatments, respectively. The 6% deheated mustard powder treatment provided the most rapid reductions of E. coli O157:H7 (yielding <0.20 log CFU/g after 24 days) by an unknown mechanism and was the least detrimental (P < 0.05) to sausage texture.  相似文献   
994.
Breeder cows, cattle recently arrived at feedlots, and cattle about to be shipped for slaughter were tested for Salmonella spp. No Salmonella spp. were detected in fecal samples from breeding cows. Nineteen of 1,000 (1.9%) fecal samples from recently arrived feedlot cattle were positive for Salmonella spp. compared to only 2 of 1,000 (0.2%) fecal samples taken within 2 weeks of slaughter. The positive fecal samples were collected in 5 of 50 (10%) "recent arrival" pens tested and in 1 of 50 (2%) pens tested within 2 weeks of slaughter. The serotypes isolated were Salmonella Agona, Salmonella Enteritidis, Salmonella Typhimurium DT104, and Salmonella 4,5,12:i:-. Ground beef samples purchased from retail outlets throughout Alberta were processed for Salmonella spp. Thirteen of 1,002 (1.3%) samples were positive for Salmonella spp. The serotypes isolated from ground beef were Salmonella Anatum, Salmonella Heidelberg, Salmonella Montevideo, Salmonella Typhimurium, Salmonella Typhimurium var. Copenhagen, and Salmonella Rough-O:i:1,2. The antibiotic resistance and pulsed-field electrophoresis gel macrorestriction patterns of all isolates were compared.  相似文献   
995.
A number of environmental stressors have been hypothesized as responsible for recent increases in limb malformations in several species of North American amphibians. The purpose of this study was to generate dose-response data suitable for assessing the potential role of solar ultraviolet (UV) radiation in causing limb malformations in a species in which this phenomenon seemingly is particularly prevalent, the northern leopard frog (Rana pipiens). Frogs were exposed from early embryonic stages through complete metamorphosis to varying natural sunlight regimes, including unaltered (100%) sunlight, sunlight subjected to neutral density filtration to achieve relative intensities of 85%, 75%, 65%, 50%, and 25% of unaltered sunlight, and sunlight filtered with glass or acrylamide to attenuate, respectively, the UVB (290-320 nm) and UVB plus UVA (290-380 nm) portions of the spectrum. The experiments were conducted in a controlled setting, with continual monitoring of UVB, UVA, and visible light to support a robust exposure assessment. Full sunlight caused approximately 50% mortality of the frogs during early larval development; no significant treatment-related mortality occurred under any of the other exposure regimes, including 100% sunlight with glass or acrylamide filtration. There was a dose-dependent (p < 0.0001) induction of hindlimb malformations in the frogs, with the percentage of affected animals ranging from about 97% under unaltered sunlight to 0% in the 25% neutral density treatment. Malformations were comprised mostly of missing or truncated digits, and generally were bilateral as well as symmetrical. Filtration of sunlight with either glass or acrylamide both significantly reduced the incidence of malformed limbs. The estimated sunlight dose resulting in a 50% limb malformation rate (ED50) was 63.5%. The limb ED50 values based on measured sunlight intensities corresponded to average daily doses of 4.5 and 100 Wh x m(-2) for UVB and UVA, respectively. Exposure to sunlight also resulted in increased eye malformations in R. pipiens, however, the dose-response relationship for this endpoint was not monotonic. The results of this study, in conjunction with measured or predicted exposure data from natural settings, provide a basis for quantitative prediction of the risk of solar UV radiation to amphibians.  相似文献   
996.
The formation of volatile compounds during the Bacillus subtilis fermentation of cooked, roasted soya bean cotyledons was investigated. The materials examined were: dry roasted cotyledons; autoclaved, roasted cotyledons; and autoclaved, roasted cotyledons fermented for 18 h and 36 h at 35°C. Growth of B subtilis led to the formation of many volatile compounds. The volatile compounds formed in the largest amounts during fermentation were 3-hydroxy-2-butanone (acetoin), 2,5-dimethylpyrazine and trimethylpyrazine. Compounds present at concentrations exceeding their odour threshold values included nonanal, decanal, 1-octen-3-ol, butanedione, 3-hydroxy-2-butanone, 3-octanone, 2,5-dimethylpyrazine, 3,6-dimethyl-2-ethylpyrazine, 2-pentylfuran, dimethyl sulfide, benzaldehyde and 2-methoxyphenol. Compounds found in 18 h fermented cotyledons which were absent, or present in much lower concentrations, in roasted or autoclaved cotyledons included several aliphatic ketones, acetic acid, two aliphatic esters, several pyrazines, 2-pentylfuran, dimethyl sulphide, 2-methoxyphenol and trimethyloxazole. The total mass of volatile compounds present after 36 h incubation was less than half that present after 18 h. This was mainly due to the disappearance of 3-hydroxy-2-butanone, 2,5-dimethylpyrazine and 2,6-dimethylpyrazine. The biogenesis of the volatile compounds is discussed. © 1997 SCI.  相似文献   
997.
Examined the degree to which psychopaths can learn to modify their spontaneous skin resistance responses (SSRRs) using intructions and biofeedback. Ten clinically defined psychopaths and 12 control Ss were tested, using a within-S design. Ss were required to increase and decrease the frequency of SSRRs, first without feedback, then with biofeedback training, and finally without feedback. During prefeedback with instructions alone, control Ss were able to raise SSRRs relative to resting baselines, but psychopaths showed no SSRR control. After 16 min of biofeedback training, both groups were able to raise and lower their SSRRs to a comparable degree. The results for heart rate, measured at the same time, presented the opposite pattern; during prefeedback with instructions alone, both groups produced comparable increases in heart rate, but in postfeedback the controls maintained heart rate whereas the psychopaths did not. Data suggest that psychopaths are as capable of learning to voluntarily regulate electrodermal activity as are controls, but they still differ in autonomic patterning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
998.
Reports an error in the original article by J. L. Horn and G. Donaldson (American Psychologist, 1976, Vol 31[10], 701–719; see record 1977-07954-001). On page 717 the sentence that begins with the last line of the left-hand measure should read "The effect is shown by comparing (e.g., over 5 years) the first-test and retest average scores for those who do and those who do not survive for a while longer (another 5 years).' (The following abstract of this article originally appeared in PA, Vol 57:7954). Considers that careful review of the logical and empirical bases for the myth argument indicates that there is little to justify it. There is evidence that some of the abilities of intelligence improve throughout substantial parts of adulthood, or at least do not decline as much or as early as other abilities. Perhaps some individuals manage to avoid decrements which affect others. Positive sampling bias and wishful thinking in the conduct and interpretation of research tend to work against finding support for any decrement hypothesis that may be true. Yet the evidence suggests that if one lives long enough, decrement in at least some of the important abilities of intelligence is likely to occur. However, the reasonable interpretations that are possible for existing results are too complex… (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
999.
Reports an error in the the article "Effects of Assigned and Participative Goal Setting on Performance and Job Satisfaction" by Gary P. Latham and Gary A. Yukl (Journal of Applied Psychology. Vol 61(2) Apr 1976, 166-171). The last paragraph in the Results section subtitled "Manipulation Check and Reliability of Measures" on page 168 was a repetition of the previous paragraph. It should be changed to read as follows: The internal consistency of the satisfaction measure was .83, The stability of the satisfaction scale, as estimated by the correlation between the before and after measures of satisfaction, was .70 (p 1977-30702-001.) Evaluated the job performance of 41 female typists under participative or assigned goal setting conditions over a 10-wk period. Significant productivity improvement occurred in both conditions during the 2nd 5 wks. There was no significant difference between conditions with respect to goal difficulty or frequency of goal attainment. Job satisfaction declined slightly in both conditions. Individual trait measures such as need for independence did not moderate the effects of either type of goal setting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
1000.
Reviews the literature on death anxiety as it relates to psychosocial care of the terminally ill. The literature strongly supports the need for caregivers to understand their own fears and feelings in order to deal with terminal patients. The negative potential consequences of misunderstood feelings about death are discussed as well as several major correlates (sex, socioeconomic status, occupation, general anxiety, and level of consciousness). Some results of groups emphasizing ventilation of fears about death are also reviewed briefly. Their positive effects on treatment suggest the value of gaining more accurate understanding of death anxiety through future research. (French abstract) (44 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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