全文获取类型
收费全文 | 7559篇 |
免费 | 717篇 |
国内免费 | 544篇 |
出版年
2024年 | 16篇 |
2023年 | 131篇 |
2022年 | 130篇 |
2021年 | 156篇 |
2020年 | 324篇 |
2019年 | 372篇 |
2018年 | 310篇 |
2017年 | 385篇 |
2016年 | 325篇 |
2015年 | 263篇 |
2014年 | 290篇 |
2013年 | 985篇 |
2012年 | 210篇 |
2011年 | 285篇 |
2010年 | 228篇 |
2009年 | 293篇 |
2008年 | 393篇 |
2007年 | 439篇 |
2006年 | 406篇 |
2005年 | 357篇 |
2004年 | 320篇 |
2003年 | 256篇 |
2002年 | 215篇 |
2001年 | 145篇 |
2000年 | 112篇 |
1999年 | 81篇 |
1998年 | 87篇 |
1997年 | 67篇 |
1996年 | 52篇 |
1995年 | 80篇 |
1994年 | 36篇 |
1993年 | 35篇 |
1992年 | 21篇 |
1991年 | 17篇 |
1990年 | 10篇 |
1989年 | 16篇 |
1988年 | 14篇 |
1985年 | 79篇 |
1984年 | 94篇 |
1983年 | 61篇 |
1982年 | 67篇 |
1981年 | 67篇 |
1980年 | 77篇 |
1979年 | 71篇 |
1978年 | 99篇 |
1977年 | 78篇 |
1976年 | 77篇 |
1975年 | 63篇 |
1974年 | 62篇 |
1973年 | 52篇 |
排序方式: 共有8820条查询结果,搜索用时 15 毫秒
921.
李黔宁 《医学与哲学(人文社会医学版)》1998,(11)
在生理水平的血管壁切应力属于优性因子,能促进血管重建,抑制内皮细胞凋亡,调节内皮细胞分泌功能,使内皮细胞形态产生适应性变化;而显著升高或降低的血管壁切应力则属于非优因子,导致高血压恶性循环发生、促进动脉粥样硬化及动脉血栓形成。实现切应力非优向优转化的重要途径是降低高血压和选择性阻断切应力对基因表达的调节 相似文献
922.
We construct a faithful interpretation of ukasiewicz's logic in product logic (both propositional and predicate). Using known facts it follows that the product predicate logic is not recursively axiomatizable.We prove a completeness theorem for product logic extended by a unary connective of Baaz [1]. We show that Gödel's logic is a sublogic of this extended product logic.We also prove NP-completeness of the set of propositional formulas satisfiable in product logic (resp. in Gödel's logic). 相似文献
923.
Yuichi Shoda Walter Mischel Suzanne M. Miller Michael Diefenbach Mary B. Daly Paul F. Engstrom 《Journal of clinical psychology in medical settings》1998,5(1):3-17
Genetic testing for inherited cancer susceptibility, based on the recently identified. BRCA1 and BRCA2 genes, will soon be available on a large scale. However, at present, genetic test results do not lead to clearly indicated diagnostic or preventive measures, and the nature of the psychological impact of BRCA1/2 testing is still largely unknown. This uncertainty, combined with preliminary evidence suggesting significant individual differences in reactions to genetic susceptibility feedback, constitutes a unique challenge for any individual contemplating such testing. We outline the nature of this challenge and then propose an intervention strategy designed to help individuals make deeply processed and psychologically well-informed decisions with regard to their genetic susceptibility. The intervention is guided by recent research findings and theory on the cognitive–emotional processing of cancer-risk information. Specifically, the goal is to prepare the individual for genetic testing by (1) cognitively and emotionally activating, or preliving, the individual's potential reactions to testing feedback; (2) facilitating accurate appraisal of the individual's cognitive–emotional reactions; and (3) enabling the individual to process these reactions through the use of well-established clinical techniques. 相似文献
924.
Rhoda K. Unger 《Journal of Adult Development》1998,5(3):163-170
This article presents evidence for the view that an important precursor to a feminist identity is a sense of one's own marginality plus a redefinition of what that marginality means. Choosing marginality appears to be a highly adaptive strategy for social activists who can pass as members of the dominant majority. Women leaders in psychology appear to be more likely to be Jewish and/or to be from working class backgrounds than one would expect by chance. An examination of their autobiographical narratives indicates that many of them have actively engaged their marginal identities and redefined them into a source of strength. This article also explores the historical and contextual factors that influence overt identification with some form of marginality. These factors include historical differences in the danger due to a particular stigmatizing social label, familial social activism, and the social power possessed by an individual woman. Finally, it is argued that positive marginality appears to promote an awareness that injustice is rooted in structural processes rather than personal inadequacy. 相似文献
925.
Jane S. Blake-Mortimer Anthony H. Winefield Ainsley H. Chalmers 《International journal of stress management》1998,5(1):57-75
Previously we showed that stress and depression could result in a 50% lowering of lymphocytic 5-ectonucleotidase (NT) which could be resolved by a diet high in antioxidants. This study suggested that high levels of free radicals mediated by stress/depression may be involved in lowering NT activities. The aim of the present study was to assess whether oxygen radicals could directly affect NT and whether excess free radicals generated in stress/depression may affect tissue ascorbate stores. Exam-stressed students and depressed patients were compared respectively to these students at low stress and depressed patients on high antioxidant intakes. In this study, NT correlated positively with tissue ascorbate stores. A range of antioxidants were tested as possible inhibitors of oxy radical interaction with NT using nitroblue tetrazolium reduction to for-mazan with superoxide anion. At physiological plasma concentrations, ascorbate inhibited this reduction but dehydroascorbate, tocopherol, retinol, selenium, urate, and reduced glutathione were ineffective. Superoxide anion directly reduced lymphocytic NT activity and this effect was reversed by either 100 molar ascorbate in vitro or a high antioxidant intake in vivo. In conclusion, the low NT activities and ascorbate stores found in stressed/depressed people appear to be mediated by higher levels of free radicals reported in these subjects. These conclusions are consistent with published reports of (1) normal NT levels in melancholic patients on high antioxidant diets; (2) heightened inflammatory reponses during stress/depression; (3) low serum levels of zinc in depressed patients. 相似文献
926.
927.
928.
Christopher Kaczor 《Christian Bioethics: Non-Ecumenical Studies in Medical Morality》1998,4(2):183-201
Aquinas's conception of the relationship of faith and reason calls into question the arguments and some of the conclusions advanced in contributions to the debate on physician-assisted suicide by David Thomasma and H. Tristram Engelhardt. An understanding of the nature of theology as based on revelation calls into question Thomasma's theological argument in favor of physician-assisted suicide based on the example of Christ and the martyrs. On the other hand, unaided reason calls into question his assumptions about the nature of death as in some cases a good for the human person. Finally, if Aquinas is right about the relationship of faith and reason, Engelhardt's sharp contrast between "Christian" and "secular" approaches to physician-assisted suicide needs reconsideration, although his conclusions about physician-assisted suicide would find support. 相似文献
929.
John B Miner 《Journal of Vocational Behavior》1974,5(2):241-250
Studies were conducted with samples of students from four different universities to determine if male-female differences in motivation to manage existed. Although differences were not found among students majoring in the field of education, females in business administration and the liberal arts did prove to have lower managerial motivation scores than the comparable male samples. These findings are discussed in terms of their relationships to sex discrimination, prospective managerial talent shortages and the vocational guidance of female college students. 相似文献
930.