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   59070篇
  免费   3237篇
  国内免费   218篇
耳鼻咽喉   761篇
儿科学   1477篇
妇产科学   1374篇
基础医学   8174篇
口腔科学   3788篇
临床医学   4832篇
内科学   12907篇
皮肤病学   1473篇
神经病学   5343篇
特种医学   1355篇
外国民族医学   1篇
外科学   6591篇
综合类   354篇
一般理论   13篇
预防医学   5771篇
眼科学   1095篇
药学   4220篇
中国医学   402篇
肿瘤学   2594篇
  2023年   495篇
  2022年   1072篇
  2021年   1986篇
  2020年   1176篇
  2019年   1790篇
  2018年   2153篇
  2017年   1429篇
  2016年   1589篇
  2015年   1844篇
  2014年   2425篇
  2013年   3055篇
  2012年   4643篇
  2011年   4909篇
  2010年   2565篇
  2009年   2082篇
  2008年   3578篇
  2007年   3572篇
  2006年   3189篇
  2005年   2961篇
  2004年   2825篇
  2003年   2404篇
  2002年   2219篇
  2001年   1178篇
  2000年   1135篇
  1999年   908篇
  1998年   360篇
  1997年   254篇
  1996年   241篇
  1995年   202篇
  1994年   184篇
  1993年   134篇
  1992年   375篇
  1991年   363篇
  1990年   330篇
  1989年   255篇
  1988年   247篇
  1987年   237篇
  1986年   198篇
  1985年   186篇
  1984年   176篇
  1983年   145篇
  1982年   88篇
  1981年   95篇
  1980年   92篇
  1979年   121篇
  1978年   91篇
  1973年   69篇
  1971年   81篇
  1970年   68篇
  1967年   83篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Background. Accepted practices of informed consent often result in suboptimal patient understanding of research studies.Methods. This pilot study aimed to assess trial-specific tailored materials, compared to a widely used generic booklet about clinical trials, randomly assigned to 118 candidates for cancer clinical trials. Study outcomes were: satisfaction with decision-making; satisfaction with materials; and subjective understanding of the clinical trial.Results. There were no major differences between groups. Participants rated tailored materials higher as a useful reference.Conclusions. Trial-specific materials hold utility for reference during clinical trials. Studies of informed consent are feasible, although important factors limit research.  相似文献   
42.
Successful pregnancy in primary glomerular disease   总被引:2,自引:0,他引:2  
The course of 66 pregnancies was studied in 48 women with primary glomerular diseases. In all cases diagnoses were established by biopsy before pregnancy. They were: membranoproliferative glomerulonephritis in 16 patients, focal glomeruloesclerosis in 13, IgA nephropathy in 10, membranous nephropathy in seven and focal glomerulonephritis in two women. The clinical status of the nephropathy before conception was that 43 had only mild renal dysfunction, five had moderate renal insufficiency, serum creatinine (1.3 to 1.9 mg%), eight women had hypertension (150/100 mm Hg) and eight had nephrotic range proteinuria. Their clinical course was compared with a control group of 36 women with primary glomerular disease who did not become pregnant, and were matched for similar age, histological type, and status of nephropathy (renal function, blood pressure and proteinuria). After one year and at the end of the five year follow-up period, the incidence of hypertension, proteinuria, and renal failure was similar in the two groups. The fetal survival rate was 92%; 51 pregnancies ended in full-term delivery, with a mean birthweight of 3,242 +/- 320 g. There were seven pre-term deliveries (2,170 +/- 135 g), three small for gestational-age (2,340 +/- 135 g), two stillbirths and three spontaneous abortions. These patients had more pre-term deliveries (10.6%) and perinatal mortality (31%) than a normal population (5.5% and 9.6%, respectively). Blood pressure increased during pregnancy in 13 women; in 10 it was reversible, and in four it persisted after delivery. Ten gravidas developed increased proteinuria (reversible in six of them) and two others developed permanent impairment of renal function.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
43.
Semi-structured interviews were conducted with a cohort of 22 test applicants who requested Huntington's disease (HD) predictive testing in South Wales, and a random sample of 32 non-requesters, drawn from the South Wales HD register. Apart from identifying differences between the groups, the study afforded the opportunity to listen, at length, to at-risk individuals' accounts of living at risk and their thoughts about predictive testing and genetic services. Emergent themes included difficulties in family communication and the uncertainties inherent in being at risk and undergoing testing. Important factors in decision making about testing were: moral imperatives to clarify one's genetic status; views about the controllability of the future; family attitudes and norms; and the impact of a test result on family members. At-risk individuals' perceptions of the genetics service were that contact with the service would result in pressure to be tested and a need for test applicants to present a favourable view of coping capacities to secure testing. In addition, there was an expectation of ongoing contact with HD families at the initiative of the service providers. Implications of the findings for the way in which predictive testing services are structured and introduced to the at-risk population are discussed.  相似文献   
44.
We report the clinical, SPET, immunohistochemical and DNA features of an early-onset familial Alzheimer's disease (FAD) in an Argentine pedigree of South American indian ethnic background. Pedigree spans 5 generations comprising more than 110 biological relatives. Clinical data supported the diagnosis of early onset FAD (mean age at onset 38.9 years) in 10 family members, including 3 with pathological confirmation (mean age at death 48.5). The pattern of transmission suggested autosomal dominant inheritance. Prominent features were mood changes, early language impairment, myoclonus, seizures and cerebellar signs. SPET displayed bilateral frontal, temporo-parietal and cerebellar hypoperfusion in early stages and in an asymptomatic member at risk, suggesting that SPET may have predictive value in this family. Immunohistochemistry showed β amyloid deposits within neuritic plaques and vessel walls and no anti-PrP immunoreactivity. DNA analysis showed no abnormalities in the β amyloid precursor protein gene. The identification of additional genetic defects in well characterized independent FAD pedigrees will contribute to the understanding of the pathogenesis of Alzheimer's disease.  相似文献   
45.
Regulation of T cell-dependent immune responses is mediated in part by bone marrow-derived antigen presenting cells (APC) that (a) process and present antigens which engage the T cell receptor and (b) secrete cytokines that influence the threshold of T cell activation. The anterior chamber of the eye is lined by the corneal endothelium (which rests on a stroma and epithelium that is devoid of class II MHC + APC) and iris/ciliary body (which contain significant numbers of bone marrow-derived cells, one third of which are class II MHC +). When tested in vitro, these potential APCs fail to present antigens in a form that activates T cells. Moreover, iris/ciliary body cells actually suppress activation of T cells exposed to antigens on conventional APC. In addition, aqueous humor under normal circumstances contains factors (one of which is TGFB) that are potent inhibitors of antigen-driven T cell activation, but spare other aspects of T cell function. Evidence suggests that the bone marrow-derived cells in iris/ciliary body are the source of this factor. Thus, the anterior chamber contains powerful forces that can prevent induction and can suppress expression of T cell mediated immunity. It is proposed that these forces are responsible for immunologic privilege and anterior chamber associated immune deviation, and for suppressing pathologic proliferation and inflammation in the anterior segment of the eye.  相似文献   
46.
Carpal osteolysis: an unusual entity treated by renal transplantation   总被引:1,自引:0,他引:1  
P Ros  E Pelaez  N Gallego  J Corbatón  J Ortu?o 《Nephron》1990,55(4):434-435
  相似文献   
47.
48.
49.
50.
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