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   5352篇
  免费   345篇
  国内免费   14篇
耳鼻咽喉   78篇
儿科学   200篇
妇产科学   101篇
基础医学   686篇
口腔科学   104篇
临床医学   473篇
内科学   1310篇
皮肤病学   344篇
神经病学   360篇
特种医学   164篇
外科学   730篇
综合类   39篇
一般理论   7篇
预防医学   384篇
眼科学   64篇
药学   311篇
中国医学   2篇
肿瘤学   354篇
  2023年   52篇
  2022年   74篇
  2021年   122篇
  2020年   103篇
  2019年   151篇
  2018年   145篇
  2017年   121篇
  2016年   145篇
  2015年   121篇
  2014年   199篇
  2013年   277篇
  2012年   334篇
  2011年   355篇
  2010年   180篇
  2009年   199篇
  2008年   354篇
  2007年   311篇
  2006年   332篇
  2005年   294篇
  2004年   256篇
  2003年   265篇
  2002年   248篇
  2001年   63篇
  2000年   42篇
  1999年   63篇
  1998年   52篇
  1997年   38篇
  1996年   38篇
  1995年   47篇
  1994年   31篇
  1993年   24篇
  1992年   30篇
  1991年   28篇
  1990年   29篇
  1989年   25篇
  1988年   19篇
  1987年   21篇
  1986年   30篇
  1985年   16篇
  1984年   24篇
  1983年   27篇
  1982年   15篇
  1981年   20篇
  1980年   17篇
  1979年   13篇
  1973年   14篇
  1972年   12篇
  1971年   11篇
  1970年   14篇
  1967年   19篇
排序方式: 共有5711条查询结果,搜索用时 0 毫秒
1.
2.
3.
Treatment of non-seminomatous testicular cancer often leadsto infertility due to anejaculation/retrograde ejaculation andpoor sperm quality. In these men spermatozoa may be obtainedby transrectal electroejaculation (TE), but the optimal strategyfor assisted procreation in these couples is not known. Ouraim was to examine whether TE and conventional in-vitro fertilization(IVF) would be successful. A total of 10 couples, with long-standinginfertility due to anejaculation or retrograde ejaculation aftertreatment for testicular cancer 5–14 years earlier, werereferred to our unit. All men underwent diagnostic TE undergeneral anaesthesia. Spermatozoa were recovered in nine cases.The antegrade fraction was prepared and used for IVF. Spermquality was variable and conventional IVF was considered impossiblein three cases. Altogether six IVF treatment cycles in six couplesresulted in five pregnancies, of which four resulted in a deliveryand one resulted in a spontaneous abortion. One additional pregnancyis ongoing after transfer of cryopreserved embryos. The fertilizationrate was 54% (33/61) and the cleavage rate was 97% (32/33).No complications relating to the procedure have been encountered.  相似文献   
4.
Semantic verbal fluency tasks are commonly used in neuropsychological assessment. Investigations of the influence of level of literacy have not yielded consistent results in the literature. This prompted us to investigate the ecological relevance of task specifics, in particular, the choice of semantic criteria used. Two groups of literate and illiterate subjects were compared on two verbal fluency tasks using different semantic criteria. The performance on a food criterion (supermarket fluency task), considered more ecologically relevant for the two literacy groups, and an animal criterion (animal fluency task) were compared. The data were analysed using both quantitative and qualitative measures. The quantitative analysis indicated that the two literacy groups performed equally well on the supermarket fluency task. In contrast, results differed significantly during the animal fluency task. The qualitative analyses indicated differences between groups related to the strategies used, especially with respect to the animal fluency task. The overall results suggest that there is not a substantial difference between literate and illiterate subjects related to the fundamental workings of semantic memory. However, there is indication that the content of semantic memory reflects differences in shared cultural background--in other words, formal education--, as indicated by the significant interaction between level of literacy and semantic criterion.  相似文献   
5.
Posttraumatic enophthalmos is a cosmetic orbital deformity that may induce a secondary visual dysfunction. Two case reports are presented which review the pathophysiology, incidence, clinical and radiological examination, and treatment of posttraumatic enophthalmos.  相似文献   
6.
7.
8.
Sex-specific effects for body mass index (BMI) were explored in a newly established, population-based Norwegian twin panel. The sample includes 5,864 individuals, aged 18–25 years, who responded to a questionnaire containing items for zygosity classification, height, weight, health, health-related behaviors, well-being, and demographic information. Among the 2,570 intact pairs who returned the questionnaire there were 416 identical (MZ) male pairs, 387 fraternal (DZ) male pairs, 528 MZ female pairs, 443 DZ female pairs, and 796 unlike-sexed pairs. Alternate sets of models testing for either sex-specific genetic or environmental parameters were evaluated using structural equation analysis. Results from the most parsimonious model indicated that the genes contributing to variation in BMI are not identical for men and women; rather, some genetic effects were shared by the sexes and some were unique to each sex. Total variation in BMI could be explained by sex-specific additive genetic effects, as well as genetic and non-shared environmental effects common to men and women. Estimates of heritability were .708 for men and .789 for women, and the male-female genetic correlation was 0.622. The series of models specifying sex-specific shared environment also fit the data and suggests that shared environmental factors may be important for males but not for females. The findings raise questions concerning the relationship between sex-specific effects for BMI and sex differences in health outcomes. ©1995 Wiley-Liss, Inc.  相似文献   
9.
Appendicitis is the commonest acute surgical emergency of childhood, and occurs in approximately 2–4 per 1000 infants. It is usually seen in infants older than 5 years but can occur at any age. Atypical clinical findings are seen in 30–50% of children, especially the younger ones, and often leads to a delayed diagnosis. Preoperative clinical assessment alone has yielded an accuracy ranging between 70 and 90% but is associated with a normal appendectomy rate of 13–25%. Preoperative imaging using the graded compression US technique and/or different helical CT techniques has been able to reduce this rate to 3–7% without an increase in perforation rate. An extensive review of the literature revealed several papers examining the accuracy of different imaging modalities and strategies of acute appendicitis in children. The reported sensitivity of US varied between 87 and 95%, vs 95–97% for helical CT, while the specificity ranged between 85 and 98% for US and 94 and 97% for helical CT. Only one truly randomised study was found, showing that compared with US alone, a combination of US and helical CT increased the sensitivity from 86 to 99%, while the specificity decreased from 95 to 89%. We conclude that imaging should be performed in all children with suspected appendicitis and that US should be the initial procedure with CT as a complementary tool.  相似文献   
10.
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