全文获取类型
收费全文 | 1639503篇 |
免费 | 136088篇 |
国内免费 | 3495篇 |
专业分类
耳鼻咽喉 | 21974篇 |
儿科学 | 53897篇 |
妇产科学 | 47323篇 |
基础医学 | 232049篇 |
口腔科学 | 47861篇 |
临床医学 | 144532篇 |
内科学 | 323764篇 |
皮肤病学 | 34755篇 |
神经病学 | 133802篇 |
特种医学 | 66110篇 |
外国民族医学 | 476篇 |
外科学 | 249171篇 |
综合类 | 41777篇 |
现状与发展 | 4篇 |
一般理论 | 545篇 |
预防医学 | 125031篇 |
眼科学 | 37085篇 |
药学 | 124594篇 |
11篇 | |
中国医学 | 3921篇 |
肿瘤学 | 90404篇 |
出版年
2018年 | 15919篇 |
2016年 | 13916篇 |
2015年 | 16321篇 |
2014年 | 22323篇 |
2013年 | 33376篇 |
2012年 | 45168篇 |
2011年 | 47402篇 |
2010年 | 27949篇 |
2009年 | 26803篇 |
2008年 | 45209篇 |
2007年 | 47459篇 |
2006年 | 48095篇 |
2005年 | 46577篇 |
2004年 | 45838篇 |
2003年 | 43666篇 |
2002年 | 42615篇 |
2001年 | 76670篇 |
2000年 | 79270篇 |
1999年 | 67236篇 |
1998年 | 18082篇 |
1997年 | 16619篇 |
1996年 | 16602篇 |
1995年 | 16241篇 |
1994年 | 15282篇 |
1993年 | 14390篇 |
1992年 | 55890篇 |
1991年 | 54161篇 |
1990年 | 52937篇 |
1989年 | 51220篇 |
1988年 | 47522篇 |
1987年 | 46844篇 |
1986年 | 44572篇 |
1985年 | 43088篇 |
1984年 | 32237篇 |
1983年 | 27716篇 |
1982年 | 16237篇 |
1981年 | 14507篇 |
1980年 | 13635篇 |
1979年 | 30620篇 |
1978年 | 21157篇 |
1977年 | 17848篇 |
1976年 | 16757篇 |
1975年 | 17636篇 |
1974年 | 21582篇 |
1973年 | 20773篇 |
1972年 | 18946篇 |
1971年 | 17849篇 |
1970年 | 16361篇 |
1969年 | 15341篇 |
1968年 | 14007篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
995.
U. Bolm-Audorff S. Brandenburg T. Brüning H. Dupuis R. Ellegast G. Elsner K. Franz H. Grasshoff V. Grosser L. Hanisch B. Hartmann E. Hartung K. G. Hering G. Heuchert M. Jäger J. Krämer Dr. A. Kranig E. Ludolph A. Luttmann A. Nienhaus W. Pieper K.-D. Pöhl T. Remé D. Riede G. Rompe K. Schäfer S. Schilling E. Schmitt F. Schröter A. Seidler M. Spallek M. Weber 《Trauma und Berufskrankheit》2005,7(3):211-252
Occupational diseases Nos. 2108 and 2110 correspond to intervertebral disc-related diseases of the lumbar spine from many years of carrying or lifting heavy loads, occupations in extreme postures of full flexion or oscillation of the whole body when seated, and which compel the cessation of all activities which are or could be the cause for the origin, exacerbation or recurrence of the disease. These occupational diseases came into force at the start of 1993, but there have been considerable problems in their implementation. The present Part I of the contribution is the result of the work of an interdisciplinary study group and contains medical criteria for the assessment of possibly strain-related clinical characteristics and the evaluation of other possible causes. Part II is to be published in Volume 4/2005 and will deal with questions related to forced cessation and to the assessment of the loss of earning ability. Agreement was reached in many areas related to the assessment of occupational claims. This should allow for evidence-based decision making in the future for the occupational diseases Nos. 2108 and 2110. 相似文献
996.
Hong Li Fassil Ketema Anne M Sill Kristen M Kreisel Farley R Cleghorn Niel T Constantine 《International journal of infectious diseases》2007,11(5):459-465
OBJECTIVES: We sought to modify the Serodia HIV-1/HIV-2 particle agglutination assay (PA), a simple and cost-effective HIV assay that is used globally for the detection of HIV antibodies, as a sensitive/less sensitive test (S/LS) to identify recently infected individuals and to estimate HIV incidence. METHODS: The Serodia PA test was modified as an S/LS test (PA-LS) by using HIV antigen-coated gelatin particles at a dilution of 1:68 and a specific diluent, and calibrated using 37 HIV clade B seroconversion panels (309 samples) from Trinidad and from a commercial source that were tested at dilution intervals from 1:10 to 1:80,000. The greatest sensitivity for correctly classifying samples from recent and established infections was determined by receiver operator curve (ROC) analysis. RESULTS: At a 1:40,000 sample dilution and a days post-seroconversion cutoff of 190 days, the PA-LS test yielded a 97% sensitivity for classifying recent and established infection samples. Furthermore, at a 1:20,000 dilution, the positive predictive value for correctly identifying recently infected individuals was 99%. The PA-LS test offers a 30-44-fold cost saving over currently available S/LS tests. CONCLUSION: A modified, low cost and simple-to-perform PA test is appropriate for use in resource-limited countries, and has exhibited excellence in distinguishing recent from established HIV infection. 相似文献
997.
998.
Multiple intrahippocampal injections of gallamine impair performance of a representational memory task in rats. The binding of [3H]-(-)-quinuclidinyl benzilate (QNB) to rat brain sections was measured to determine if changes in receptor binding were associated with the deleterious effects of gallamine. [3H]-(-)-QNB binding to sections taken from gallamine-injected animals was compared with binding in saline-injected control animals. Autoradiographic analyses indicated an increase in [3H]-(-)-QNB binding sites within all layers of the cerebral cortex and in the superior colliculus in gallamine-treated animals as compared to saline-injected controls. Significant increases were noted in cortical layers IV and V (P less than 0.025) in gallamine-treated animals. No significant changes (P greater than 0.05) in the number of binding sites were observed in the hippocampus, neostriatum or various thalamic nuclei. The ability of unlabeled pirenzepine, gallamine and carbamylcholine to inhibit 0.2 nM [3H]-(-)-QNB binding also was measured to determine changes in the distribution of receptor subtypes. No significant changes were observed in any brain region for the binding of the selective antagonists pirenzepine and gallamine or the agonist carbamyl-choline. Although other possibilities are considered, the data suggest that an increase in the number of muscarinic receptors may contribute to the observed behavioral deficits associated with long-term gallamine treatment. 相似文献
999.
1000.
Bradley J Catalone Shendra R Miller Mary Lee Ferguson Dan Malamud Tina Kish-Catalone Nina J Thakkar Fred C Krebs Mary K Howett Brian Wigdahl 《Biomedicine & Pharmacotherapy》2005,59(8):430-437
C31G, which has potent activity against the human immunodeficiency virus type 1 (HIV-1) and an established record of safety in animal studies and human trials, is a microbicidal agent comprised of a buffered equimolar mixture of two amphoteric, surface-active agents: an alkyl amine oxide (C14AO) and an alkyl betaine (C16B). Studies of long-term in vitro exposure to C31G and its constituents have suggested that the components of C31G may contribute differentially to its toxicity and efficacy. In the present studies, in vitro assays of cytotoxicity and anti-HIV-1 activity demonstrated that C16B was slightly less cytotoxic compared to either C31G or C14AO, whereas the anti-HIV-1 activities of C31G and its individual constituents were similar. In the murine model of cervicovaginal microbicide toxicity, in vivo exposure to C14AO resulted in severe cervical inflammation followed by a delayed disruption of the columnar epithelium. In contrast, exposure to C16B caused severe cervical epithelial disruption and a secondary, less intense inflammatory response. These results demonstrate that (i) there are both mechanistic and temporal differences in toxicity associated with the components of C31G not necessarily predicted by in vitro assessments of cytotoxicity and (ii) contributions of each component to the anti-HIV-1 activity of C31G appear to be equal. In addition, these findings indicate that direct and indirect mechanisms of in vivo toxicity can be observed as separate but interrelated events. These results provide further insight into the activity of C31G, as well as mechanisms potentially associated with microbicide toxicity. 相似文献