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81.
Analysis of characteristic odors from human male axillae 总被引:7,自引:0,他引:7
Xiao -nong Zeng James J. Leyden Henry J. Lawley Kiyohito Sawano Isao Nohara George Preti 《Journal of chemical ecology》1991,17(7):1469-1492
A number of studies concerning the analysis of axillary odors have assumed that the characteristic odor produced in the axillae is due to volatile steroids and isovaleric acid. Organoleptic evaluation of Chromatographic eluants from axillary extracts was employed to isolate the region in the chromatogram where the characteristic odor eluted. The odor of the dissolved eluant was eliminated when it was treated with base, suggesting that acids make up the characteristic axillary odor. Subsequent extraction of the pH-adjusted axillary extract in conjunction with organoleptic evaluation of the Chromatographic eluant, preparative gas chromatography, and analysis by GC-MS as well as GC-FTIR showed the presence of a number of C6 to C11 straight-chain, branched, and unsaturated acids as important contributors to the axillary odor. The major odor component is (E)-3-methyl-2-hexenoic acid. Three homologous series of minor components are also important odor contributors; these consist of the terminally unsaturated acids, the 2-methyl-C6 to -C10 acids and the 4-ethyl-C5 to -C11 acids. These types of acids have not been reported previously as components of the human axillary secretions and have not been proposed previously as part of the principal odor components in this area. 相似文献
82.
在对影响体育教学质量的几种环境因素分析的基础上,提出了克服体育实践教学环境 因素的消极影响的主要措施以及正确利用这些物理因素的积极作用。 相似文献
83.
84.
Burns John W.; Kubilus Amanda; Bruehl Stephen; Harden R. Norman; Lofland Kenneth 《Canadian Metallurgical Quarterly》2003,71(1):81
Changes in maladaptive cognitions may constitute therapeutic processes of multidisciplinary pain programs. A cross-lagged panel design was used to determine whether (a) early-treatment cognitive change predicted late-treatment outcome index change, but not vice versa; and (b) these effects remained significant with depression change controlled. Ninety chronic pain patients, in a 4-week multidisciplinary program, completed measures of catastrophizing, pain helplessness, depression, pain, interference, and activity level at pre-, mid-, and posttreatment. With depression changes controlled, early-treatment catastrophizing and pain helplessness changes predicted late-treatment outcome index changes, but not vice versa; early-treatment depression changes predicted late-treatment activity changes, but not vice versa. Findings advance understanding of pain treatment process and suggest that negative cognition changes may indeed affect improvements in treatment outcome. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
85.
Shaw Daniel S.; Gilliom Miles; Ingoldsby Erin M.; Nagin Daniel S. 《Canadian Metallurgical Quarterly》2003,39(2):189
The present study applied a semiparametric mixture model to a sample of 284 low-income boys to model developmental trajectories of overt conduct problems from ages 2 to 8. As in research on older children, 4 developmental trajectories were identified: a persistent problem trajectory, a high-level desister trajectory, a moderate-level desister trajectory, and a persistent low trajectory. Follow-up analyses indicated that initially high and low groups were differentiated in early childhood by high child fearlessness and elevated maternal depressive symptomatology. Persistent problem and high desister trajectories were differentiated by high child fearlessness and maternal rejecting parenting. The implications of the results for early intervention research are discussed, with an emphasis on the identification of at-risk parent-child dyads. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
86.
运用马克思主义历史———美学批评方法 ,结合多种批评理论 ,对《太阳之歌》诗集进行全面、系统、多角度的读解 ,肯定了它的艺术成就 ,指出它是现实主义的绚丽花朵 相似文献
87.
88.
指出当今建筑业良好的市场给建筑师们提供了展示自己作品的广大空间 ,但其精品却为之甚少。为此 ,对建筑业存在的一些问题及制约建筑师出精品的主、客观因素进行了分析 ,指出建筑师应提高自身素质 ,树立精品意识 ,增强市场竞争能力 相似文献
89.
已二醇二丙烯酸酯对真丝的接枝改性研究 总被引:2,自引:0,他引:2
研究了用二醇二丙烯酸酯为接枝单体、过硫酸铵(APS)为引发剂对真丝的接枝共聚反应,分析了接枝率的影响素,并测试了改性真丝的主要应用性能。结果表明:乳液和乙醇/水为溶剂的2种体系都能在真丝上获得较高接枝率。对于乙醇/水体系v(乙醇):v(H2O)=1:1,接枝单体20~30g/L,2%甲酸4ml,引发剂APS 0.5g/L,65~70℃接枝60min的接枝率高。改性后真丝的断裂强度、延伸度、吸湿性能都可获得改善,对酸、碱的溶解性提高,但染色性能提高不明显,对泛黄性改善一般。 相似文献
90.
P. Powell 《Information Systems Journal》1992,2(4):269-280
Abstract. Expert systems proliferate. They are now a usable and used tool in a variety of organizations. However, little research has been undertaken on the quantification of success or failure of expert system projects. By and large the only test carried out for expert system validation is one of comparison of the conclusions of the system with those of an expert or team of experts. While questioning the validity, this paper accepts that this method is being used and analyses whether or not the results obtained from this type of test should be a surprise. That is, what sort of results should be expected and to what extent do the reported ones live up to these expectations? Earlier research from the field of human information processing casts doubts on the success claims made for current expert systems. The implications of this research are then analysed in order to explore the possible redeeming features of expert systems which are not taken into account in such comparisons. The use of linear models as comparators for expert systems may prove beneficial. 相似文献