首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   670篇
  免费   10篇
电工技术   6篇
化学工业   65篇
金属工艺   7篇
机械仪表   15篇
建筑科学   18篇
矿业工程   10篇
能源动力   13篇
轻工业   52篇
水利工程   7篇
石油天然气   3篇
无线电   51篇
一般工业技术   118篇
冶金工业   250篇
原子能技术   3篇
自动化技术   62篇
  2023年   5篇
  2022年   7篇
  2021年   14篇
  2020年   3篇
  2019年   7篇
  2018年   5篇
  2016年   10篇
  2015年   6篇
  2014年   11篇
  2013年   37篇
  2012年   25篇
  2011年   32篇
  2010年   31篇
  2009年   20篇
  2008年   30篇
  2007年   29篇
  2006年   18篇
  2005年   20篇
  2004年   11篇
  2003年   20篇
  2002年   14篇
  2001年   10篇
  2000年   6篇
  1999年   16篇
  1998年   48篇
  1997年   40篇
  1996年   21篇
  1995年   23篇
  1994年   17篇
  1993年   13篇
  1992年   6篇
  1991年   4篇
  1990年   8篇
  1989年   11篇
  1988年   9篇
  1987年   9篇
  1986年   4篇
  1985年   6篇
  1984年   5篇
  1982年   7篇
  1981年   3篇
  1980年   6篇
  1978年   3篇
  1977年   3篇
  1976年   15篇
  1975年   10篇
  1970年   2篇
  1957年   2篇
  1956年   3篇
  1943年   2篇
排序方式: 共有680条查询结果,搜索用时 312 毫秒
1.
2.
3.
Diabetes mellitus positive for antibodies to glutamate decarboxylase is heterogeneous as far as the degree of impairment of endogenous insulin release, though antibodies to glutamate decarboxylase are the most useful marker for future insulin deficiency. To investigate what determines the prognosis of diabetes mellitus positive for antibodies to glutamate decarboxylase, we measured HLA-DRB1 alleles in three groups: 77 cases of insulin-dependent diabetes mellitus (IDDM), 44 of non-insulin-dependent diabetes mellitus (NIDDM) with secondary failure of oral hypoglycemic therapy, and 22 of NIDDM well controlled by diet and/or sulfonylurea agents. The proportion of susceptible and resistant alleles to IDDM determined the degree of insulin deficiency, and comparison of IDDM to NIDDM well controlled by diet and/or sulfonylurea agents revealed significant differences in DRB1*0405 (P < 0.05; RR = 2.82 and RR = 0.89, respectively) and DRB1*1502 (P < 0.001; RR = 0.02 and RR = 2.19, respectively). This study revealed that HLA-DRB1 alleles contribute to determining the prognosis of Japanese diabetes mellitus positive for antibodies to glutamate decarboxylase.  相似文献   
4.
Objective: Guided by the extended parallel process model (EPPM), the objective was to assess control processes dominant in influenza behavior decisions. Design: Cross-sectional survey. Results: Response rate was 31% (n=968). Regarding influenza risk, 59% were in danger control. Those in fear control were more likely to report influenza infection (p=.000). In the nonvaccinated, those in fear control were more likely to indicate not knowing where to get the vaccine (p=.016) and that it was unavailable (p=.027), and those in danger control believed they did not need it (p=.023). Zero critical values were more likely to indicate that no health provider recommended the shot (p=.002). Conclusions: Most perceived efficacy to be stronger than threat related to influenza; according to the EPPM, they are aware of their risk but recognize their ability to avert it. For those in danger control, messages should focus on increasing perceptions of severity and susceptibility to positively affect behavior change. For those in fear control, messages should focus on efficacy only. With a critical value of zero, no threat is induced, and a high-threat/high-efficacy approach should be taken. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
5.
6.
Used in concert with the Kirchhoff transformation, implicit differentiation of the discretized boundary integral equations governing the conduction of heat in solids with temperature dependent thermal conductivity is shown to generate an accurate and economical approach for computation of shape sensitivities. For problems with specified temperature and heat flux boundary conditions, a linear problem results for both the analysis and sensitivity analysis. In problems with either convection or radiation boundary conditions, a non-linear problem is generated. Several iterative strategies are presented for the solution of the resulting sets of non-linear equations and the computational performances examined in detail. Multi-zone analysis and zone condensation strategies are demonstrated to provide substantive computational economies in this process for models with either localized non-iinear boundary conditions or regions of geometric insensitivity to design variables. A series of non-linear example problems is presented that have closed form solutions. Exact anaytical expressions tor the shape sensitivities associated with these problems are developed and these are compared with the sensitivities computed using the boundary element formulation.  相似文献   
7.
We report a 16-year-old boy, born to consanguineous parents, with mental retardation, gait disturbances and dysarthria; brain magnetic resonance showed features consistent with rhombencephalosynapsis. This condition is characterised by a hypoplastic single-lobed cerebellum. The interest of this case is the presence of common ancestors, pointing to an autosomal recessive inheritance of the malformation.  相似文献   
8.
Research has consistently documented that the quality of the therapeutic alliance is related to the outcome of diverse psychotherapies. Insufficient attention, however, has been directed at identifying the nature and magnitude of the causal relationship between the alliance and outcome. In this commentary, we discuss the major threats to causal interpretation of alliance-outcome correlations and provide suggestions for future research that would help clarify the extent to which the alliance causes positive outcomes. Assuming the alliance is a causal factor in relation to outcome, we provide recommendations for research on the alliance that would attempt to improve patient care by enhancing the alliance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
9.
Relations of heart rate and skin conductance reactions to mildly evocative empathy-inducing slides with socioemotional functioning were examined for 154 children (mean age = 9 years, 5 months). In addition, maternal expressivity was tested as a moderator of these relations. Parents and teachers rated children's socioemotional functioning, and a behavioral measure of children's regulation was obtained. Boys who exhibited higher skin conductance and higher heart rate to slides depicting negative emotions were better regulated, less emotionally intense, and better adjusted than their peers. Furthermore, boys' regulation and adjustment were positively related to such physiological responding to negative slides if maternal negative expressivity was relatively low or moderate, but not high. Fewer findings were obtained for girls or for positive slides. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
10.
An unusual case of fetal lymphangioma diagnosed before delivery is reported in a second trimester pregnant woman. The lymphangioma was suspected at 28 weeks on the basis of the ultrasound appearances and progression of the lesions with advancing gestation. MRI was used to evaluate the extent and the tissue characteristics of the lesions. Cytology of the fluid aspirated from the cystic lesions showed abundant lymphocytes and macrophages, confirming the diagnosis of a lymphangioma. The parents opted for a pregnancy termination because of the rapid growth of the lesions and the poor prognosis. It is suggested that the combination of these tests could enable the early diagnosis of these tumours at a stage when the lesion is relatively limited and accessible to therapy in utero.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号