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   1385篇
  免费   121篇
  国内免费   15篇
耳鼻咽喉   7篇
儿科学   78篇
妇产科学   24篇
基础医学   205篇
口腔科学   42篇
临床医学   120篇
内科学   349篇
皮肤病学   38篇
神经病学   77篇
特种医学   131篇
外科学   126篇
综合类   43篇
预防医学   119篇
眼科学   32篇
药学   92篇
中国医学   1篇
肿瘤学   37篇
  2023年   10篇
  2022年   24篇
  2021年   23篇
  2020年   22篇
  2019年   27篇
  2018年   49篇
  2017年   27篇
  2016年   48篇
  2015年   45篇
  2014年   58篇
  2013年   72篇
  2012年   78篇
  2011年   87篇
  2010年   74篇
  2009年   70篇
  2008年   61篇
  2007年   76篇
  2006年   53篇
  2005年   47篇
  2004年   39篇
  2003年   39篇
  2002年   23篇
  2001年   17篇
  2000年   15篇
  1999年   16篇
  1998年   47篇
  1997年   46篇
  1996年   49篇
  1995年   36篇
  1994年   23篇
  1993年   28篇
  1992年   9篇
  1991年   8篇
  1990年   8篇
  1989年   20篇
  1988年   18篇
  1987年   13篇
  1986年   14篇
  1985年   17篇
  1984年   10篇
  1983年   14篇
  1982年   7篇
  1981年   13篇
  1980年   7篇
  1979年   4篇
  1978年   5篇
  1977年   10篇
  1976年   9篇
  1975年   4篇
  1884年   1篇
排序方式: 共有1521条查询结果,搜索用时 15 毫秒
1.
2.
3.
Survey respondents' views about alcoholism as an illness, support for treatment, treatment recommendation and stigma surrounding alcoholics are examined. Subjects (N = 482) comprise a random sample of the population of Contra Costa County, California. About 91% of the respondents agree with the notion that alcoholism is an illness, but 40% also agree that alcoholics drink because they want to. More women than men support the idea that to recover alcoholics will have to quit drinking forever. The contrary is true of the idea of controlled drinking. Education and income are negatively associated with items on loss of control and controlled drinking. Respondents who have had their lives deeply affected by an alcoholic and those who report a drinking problem of their own do not differ in their opinions about alcoholism from those who do not have these characteristics. Alcoholics Anonymous is the most common form of treatment recommended by the respondents. In general, results show considerable support for treatment as well as ambivalence regarding the disease concept.  相似文献   
4.
INTRODUCTION: In patients (pts) with atrial fibrillation (AF) of more than 48 hours' duration, electrical cardioversion (ECV) should only be performed after 3 weeks of effective anticoagulation. Transesophageal echocardiography (TEE) allows earlier ECV; however, despite exclusion of thrombi in the atrium and left atrial appendage (LAA), cases of thromboembolism related to ECV have been documented in AF. To define a low-risk group for cardioversion without previous anticoagulation, pts were selected for immediate ECV if no thrombi or dynamic spontaneous echo contrast (auto-contrast) were found after TEE and if LAA velocity was more than 0.25 m/sec. METHODS AND RESULTS: We performed TEE in 31 consecutive pts referred for ECV for AF of more than 48 hours' duration and without previous anticoagulation. After TEE the pts eligible for immediate ECV began anticoagulation with low molecular weight heparin (enoxaparin), subcutaneously in therapeutic doses, together with warfarin immediately before cardioversion. Enoxaparin was continued until an INR of over 2 was reached. Based on the TEE findings, the pts were divided in 2 groups: immediate ECV, group A, 20 pts with a mean age of 62 +/- 13 years, 6 female; and conventional therapy with warfarin before ECV, group B, 11 pts, mean age of 67 +/- 10 years (p < 0.05), 2 female. None of the pts in either group had mitral stenosis or previous episodes of thromboembolism. The mean transverse diameter of the left atrium in the 31 pts was 47 +/- 4.5 mm, without statistically significant differences between the 2 groups. Of the 11 pts in group B, 3 had a thrombus in the LAA, 6 dynamic spontaneous echo contrast and the remainder LAA velocities of less than 0.25 m/sec. ECV was achieved in all the pts, with no complications. Oral anticoagulation was maintained for at least a month. At one month, sinus rhythm was maintained in 75% of group A and 45% of group B (p < 0.01). CONCLUSION: In pts with AF of more than 48 hours' duration and no previous history of thromboembolism, the use of our exclusion criteria during TEE enabled stratification of a low-risk population for immediate ECV, which was accomplished effectively and safely in 2/3 of the pts. This strategy is associated with early symptomatic improvement, and may contribute to maintenance of sinus rhythm after one month, which was significantly better than in the pts who had prolonged therapy with warfarin before ECV, despite the differences found in age and left ventricular function.  相似文献   
5.
6.
7.
8.
The aim of the study was to determine whether a prior diagnostic testicle biopsy can predict success or failure of testicular sperm extraction (TESE) with intracytoplasmic sperm injection (ICSI) in patients with non-obstructive azoospermia caused by testicular failure, and what is the minimum threshold of sperm production in the testis which must be surpassed for spermatozoa to reach the ejaculate. Forty- five patients with non-obstructive azoospermia caused by testicular failure underwent diagnostic testicle biopsy prior to a planned future TESE-ICSI procedure. The diagnostic testicle biopsy was analysed quantitatively, and correlated with the quantitative findings of spermatogenesis in patients with normal spermatogenesis, as well as with the results of subsequent attempts at TESE-ICSI. Men with non- obstructive azoospermia caused by germinal failure had a mean of 0-6 mature spermatids/seminiferous tubule seen on a diagnostic testicle biopsy, compared to 17-35 mature spermatids/tubule in men with normal spermatogenesis and obstructive azoospermia. These findings were the same for all types of testicular failure whether Sertoli cell only, maturation arrest, cryptorchidism, or post-chemotherapy azoospermia. Twenty-two of 26 men with mature spermatids found in the prior testis biopsy had successful retrieval of spermatozoa for ICSI, 12 of their partners became pregnant, and are either ongoing or delivered. The study suggests that 4-6 mature spermatids/tubule must be present in the testis biopsy for any spermatozoa to reach the ejaculate. More than half of azoospermic patients with germinal failure have minute foci of spermatogenesis which are insufficient to produce spermatozoa in the ejaculate. Prior diagnostic testicle biopsy analysed quantitatively (for the presence of mature spermatids) can predict subsequent success or failure with TESE-ICSI. Incomplete testicular failure may involve a sparse multi-focal distribution of spermatogenesis throughout the entire testicle, rather than a regional distribution. Therefore, it is possible that massive testicular sampling from many different regions of the testes may not be necessary for successful TESE-ICSI.   相似文献   
9.
β-Lactoglobulin was isolated from infant formulae that were ultra high temperature (UHT) -treated, sterilized or spray-dried. The effect of the isolated β-lactoglobulin on SfaII-fimbriae-mediated adhesion of Escherichia coli to human ileostomy glycoproteins was studied in vitro. β-Lactoglobulin isolated from sterilized formulae was found to perform significantly less well than preparations from spray-dried formulae (p = 0:05). Great heterogeneity was observed in the adhesion inhibitory capacity of β-lactoglobulin isolated from UHT-treated formulae. Therefore, no significant difference was observed between UHT-treated and sterilized formulae or spray-dried formulae (p < 0:10). It can be hypothesized that β-lactoglobulin from spray-dried and some UHT-treated infant formulae may affect the colonization of mucous membranes by E. coli strains causing neonatal septicaemia and meningitis.  相似文献   
10.
The dominant cone-rod dystrophy gene CORD6 has previously been mapped to within an 8 cM interval on chromosome 17p12-p13. The retinal- specific guanylate cyclase gene (RETGC-1), which maps to within this genetic interval and previously was implicated in Leber's congenital amaurosis, was screened for mutations within this family and in a panel of small families and individuals with various cone and cone- rod dystrophy phenotypes. A missense mutation (E837D) was identified in affected members of the CORD6 family, as well as a second missense mutation (R838C) in three other families with dominant cone-rod dystrophy. RETGC-1 is only the fourth gene to be implicated in cone-rod dystrophy and this is the first report of dominant mutations in this gene.   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