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   50859篇
  免费   4321篇
  国内免费   74篇
耳鼻咽喉   462篇
儿科学   1827篇
妇产科学   1277篇
基础医学   6789篇
口腔科学   778篇
临床医学   6246篇
内科学   9304篇
皮肤病学   913篇
神经病学   5214篇
特种医学   1164篇
外国民族医学   15篇
外科学   4918篇
综合类   630篇
一般理论   70篇
预防医学   6546篇
眼科学   1233篇
药学   3684篇
中国医学   34篇
肿瘤学   4150篇
  2023年   314篇
  2022年   514篇
  2021年   1371篇
  2020年   822篇
  2019年   1340篇
  2018年   1454篇
  2017年   1039篇
  2016年   1218篇
  2015年   1316篇
  2014年   1736篇
  2013年   2445篇
  2012年   3532篇
  2011年   3810篇
  2010年   2006篇
  2009年   1714篇
  2008年   3069篇
  2007年   3076篇
  2006年   2884篇
  2005年   2760篇
  2004年   2567篇
  2003年   2232篇
  2002年   2222篇
  2001年   834篇
  2000年   839篇
  1999年   723篇
  1998年   506篇
  1997年   428篇
  1996年   341篇
  1995年   360篇
  1994年   287篇
  1993年   272篇
  1992年   492篇
  1991年   469篇
  1990年   458篇
  1989年   451篇
  1988年   397篇
  1987年   445篇
  1986年   368篇
  1985年   368篇
  1984年   302篇
  1983年   292篇
  1982年   177篇
  1981年   172篇
  1980年   163篇
  1979年   282篇
  1978年   222篇
  1975年   163篇
  1974年   185篇
  1973年   176篇
  1972年   174篇
排序方式: 共有10000条查询结果,搜索用时 725 毫秒
71.
72.
A randomized clinical trial was performed to compare the efficacy of bilateral oophorectomy with that of tamoxifen at a dose of 10 mg twice daily in premenopausal women with metastatic breast cancer, and to examine the efficacy of each as a crossover treatment. Initial treatment responses were seen in ten of 27 patients (37%) treated with oophorectomy and seven of 26 patients (27%) treated with tamoxifen. The difference was not statistically significant. Crossover responses were seen in five of 15 patients (33%) treated with oophorectomy, including three responses in ten prior tamoxifen nonresponders; and two of 18 patients (11%) treated with tamoxifen. Time to progression distributions were not significantly different during initial treatment, and no significant differences in survival were noted. Thus, there was no overall disadvantage to the use of tamoxifen as opposed to oophorectomy as initial hormonal therapy, and a failure to respond to tamoxifen did not preclude a response to subsequent oophorectomy. Exploratory data analysis within subsets indicated consistent differential treatment effects in the visceral dominant patients. Of the 16 such patients treated with oophorectomy, eight (50%) experienced objective responses but there were no responses in the 14 patients treated with tamoxifen. In the nine visceral dominant crossover patients who had not responded to initial tamoxifen, three (33%) subsequently responded to oophorectomy. Time to progression distributions within the visceral dominant subset appeared to be better for the patients treated initially with oophorectomy. However, one must be very cautious in drawing conclusions from exploratory subset analyses, especially with the small sample size. Further studies would be required to test any hypothesis of differential organ site responsiveness.  相似文献   
73.
74.
CONTEXT & OBJECTIVE: The Ecuadorian GH receptor deficiency (GHRD)/Laron syndrome population is the only large cohort with a single GHR mutation (E180 splice), permitting identification of numerous carrier and noncarrier first-degree relatives, to ascertain effects of heterozygosity on GH-dependent IGF-I and IGFBP-3 concentrations and on growth. DESIGN: First-degree relatives (n=212) of GHRD patients had specimens taken for IGF-I, IGFBP-3, and GHR genotyping. Normal statured (n=40) and short statured (n=40) unrelated controls had measurement of IGF-I, IGFBP-3, and stature. RESULTS: There were no significant differences between heterozygous and homozygous normal relatives in IGF-I or IGFBP-3 standard deviation scores (SDS). Heterozygous relatives had lower mean height SDS than did homozygous normals, but with extensive overlap between genotype groups in both child and adult relatives. Height SDS in general did not relate to IGF-I or IGFBP-3 concentrations. CONCLUSIONS: GH-dependent IGF-I and IGFBP-3 secretion is not affected by heterozygosity for the E180 splice mutation that causes GHRD/Laron syndrome in the Ecuadorian population. Heterozygosity is associated with reduction in mean statural SDS, but this is not sufficient to be clinically important and not mediated through measurable differences in circulating IGF-I or IGFBP-3 related to genotype.  相似文献   
75.
76.
OBJECTIVES: To determine whether the increase in the incidence of injury found for the first summer season in which rugby league (RL) was played in the UK was repeated in subsequent summer seasons. DESIGN: A retrospective and prospective cohort study design. SETTING AND PARTICIPANTS: Injuries were recorded from all players who took part in 141 games over 3 summer seasons (1997 to 1999) for 1 professional team. These were compared against rates from previously collected data for 3 earlier winter and 1 summer season. ASSESSMENT OF RISK FACTORS: For each injury it was recorded in which season it occurred; how many games or training sessions, if any, were subsequently missed; the type, site and severity of injury. MAIN OUTCOME MEASURES: Injuries were reported as rate per 1000 hours, also broken down into severity according to the number of games missed and whether subsequent training sessions were missed. RESULTS: A sustained increase in injury incidence has been found comparing summer RL over RL played in the winter. There was an increase in injury rates for all sites and types, but not all reached significance. CONCLUSIONS: Data collected over 6 seasons indicate a higher risk of sustaining an injury playing summer RL, but the cause may be related to a combination of factors. These may include the ground or weather conditions associated with summer rugby, player characteristics or changes in the game itself and future research needs to investigate these further.  相似文献   
77.
78.
79.
Clinicopathologic correlation of pigmented epiretinal membranes   总被引:1,自引:0,他引:1  
We performed clinicopathologic correlation on ten surgically removed pigmented epiretinal membranes causing macular pucker. All cases occurred in eyes with existing retinal holes or tears, including eight cases of macular pucker after previous retinal detachment. These cases probably represented a limited form of proliferative vitreoretinopathy. All membranes contained pigment epithelial cells with polarity, basement membrane, and melanosomes. Cytoplasmic melanin granules accounted for the clinical feature of pigmentation in these eyes.  相似文献   
80.
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