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   21110篇
  免费   2461篇
  国内免费   24篇
耳鼻咽喉   203篇
儿科学   730篇
妇产科学   545篇
基础医学   3173篇
口腔科学   559篇
临床医学   2433篇
内科学   3556篇
皮肤病学   331篇
神经病学   1571篇
特种医学   821篇
外国民族医学   3篇
外科学   2805篇
综合类   420篇
一般理论   25篇
预防医学   2555篇
眼科学   363篇
药学   1742篇
中国医学   92篇
肿瘤学   1668篇
  2021年   222篇
  2020年   174篇
  2019年   252篇
  2018年   363篇
  2017年   219篇
  2016年   248篇
  2015年   307篇
  2014年   426篇
  2013年   603篇
  2012年   892篇
  2011年   930篇
  2010年   518篇
  2009年   489篇
  2008年   822篇
  2007年   887篇
  2006年   951篇
  2005年   915篇
  2004年   871篇
  2003年   841篇
  2002年   834篇
  2001年   807篇
  2000年   819篇
  1999年   728篇
  1998年   302篇
  1997年   263篇
  1996年   292篇
  1995年   269篇
  1994年   238篇
  1993年   206篇
  1992年   580篇
  1991年   496篇
  1990年   499篇
  1989年   448篇
  1988年   428篇
  1987年   442篇
  1986年   425篇
  1985年   387篇
  1984年   306篇
  1983年   248篇
  1982年   199篇
  1981年   184篇
  1980年   178篇
  1979年   281篇
  1978年   214篇
  1977年   177篇
  1976年   163篇
  1975年   165篇
  1974年   195篇
  1973年   187篇
  1972年   191篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
93.
Antenatal administration of glucocorticoids is often used to facilitate fetal lung maturation in cases of prematurity; however, the effects of betamethasone on maternal immune function have not been established. Therefore maternal immune function was assessed with the use of in vitro techniques. Transient and incomplete suppression of the proliferative response to the T-cell mitogen phytohemagglutinin was demonstrated as early as 24 hours after administration of betamethasone. The magnitude and duration of suppression showed a corresponding increase with advancing gestational age, but these effects were not cumulative and were always short-lived (less than 72 hours). No such suppression of the B-cell mitogen lipopolysaccharide was detected. The nonspecific cellular resistance to infection of maternal monocytes was determined through coincubation with the facultative intracellular pathogen Listeria monocytogenes. Increased phagocytic activity with a normal bactericidal effect was measured in the cell preparations obtained from recipients versus nonrecipients of betamethasone. Taken together, these findings clearly show that both specific and nonspecific immune function are intact in the preterm gravid woman after administration of betamethasone and should allay concerns over its use for reasons of infection control alone.  相似文献   
94.
In addition to the pharmacological side effects of anabolic steroids, complications may also result from the injection technique used in self administration. Two cases are presented where anabolic steroid injections resulted in knee joint sepsis and radial nerve palsy.  相似文献   
95.
Bone death in transient regional osteoporosis.   总被引:2,自引:0,他引:2  
C R Dunstan  R A Evans  N M Somers 《BONE》1992,13(2):161-165
A 48-year-old man developed transient regional osteoporosis, with hip and later knee pain. He responded well to lumbar sympathectomy. The femur and tibia adjacent to the painful knee were osteoporotic, while the medial femoral condyle showed increased uptake in a bone scan. In the femoral condyle, bone histology showed areas of dead bone undergoing osteoclastic resorption, and increased bone formation. The tibial bone was histologically normal. The partial bone death in the distal femur suggests that the disorder may be related to both avascular necrosis of bone and reflex sympathetic dystrophy.  相似文献   
96.
Abstracts     
Purpose: To analyse trends in the incidence of registered age-related macular degeneration (ARMD) in the UK since 1950 and to compare these to trends in registration of other blinding diseases —cataract, glaucoma and optic atrophy over the same time period. Methods: Calculation of standardised registration ratios for ARMD, cataract, glaucoma and optic atrophy using published registratoin data from 1950 onwards. SRRs for each sex separately were calculated, adjusting for age in 5 year age-groups. Results: The absolute number of people registered blind annually has more than doubled since 1950. After adjustment for age, annual registration rates for blindness have fallen over the past 40 years, particularly with respect to cataract and glaucoma. Standardised registration ratios for ARMD exhibit a different pattern, increasing, but not consistently, over the same time period. Conclusions: These oberservations are consistent with the hypothesis that the incidence of registrable ARMD is increasing. Changes in the diagnosis and detection of this disease, however, cannot be excluded as an alternative explantation. Analysis of trends in national registration statistics may be useful for monitoring changes in the distribution of blinding eye disease in the population.  相似文献   
97.
98.
The value of routine antibiotic prophylaxis was assessed in 362 women undergoing lower urinary tract instrumentation. A three-day course of a once-a-day dose of 1 g of cefadroxil was compared with a three-day course of 100 mg of nitrofurantoin three times a day, in a randomized investigator blinded placebo controlled study. Both study drugs were significantly more effective in preventing postinstrumentation urinary tract infections than placebo (p less than 0.003). Differences in efficacy between the two test drugs were not significant; however, side effects in the nitrofurantoin group were more frequent and severe than those in the cefadroxil group. Cefadroxil also offered the advantage of a once-daily dosing schedule.  相似文献   
99.
Glomerulopathy and nephrotic syndrome were induced in rats by intravenous puromycin aminonucleoside. Ten days after the injection of puromycin, the animals have developed heavy proteinuria. During this phase, glomerular epithelial cell endocytosis was studied by injecting a conjugate of horseradish peroxidase and poly-L-lysine. This conjugate has been shown to be endocytosed by glomerular epithelial cells. The rats were serially sacrificed from 1 min to 24 h after this injection. Peroxidase was localised cytochemically and observed at light and electron microscopy. The early events of endocytosis in glomerulopathy (namely the binding to the plasma membrane, the membrane invagination and the formation of the early vesicles) were qualitatively similar to those in the normal. The later events (the fusion of the vesicles and their movement within the cells) were inhibited. The results show that puromycin aminonucleoside damages epithelial cell endocytotic activity and affects the later processing of the conjugate within the cells.  相似文献   
100.
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