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   291392篇
  免费   38390篇
  国内免费   3601篇
耳鼻咽喉   7206篇
儿科学   7563篇
妇产科学   4455篇
基础医学   25851篇
口腔科学   4887篇
临床医学   39202篇
内科学   72548篇
皮肤病学   11738篇
神经病学   25996篇
特种医学   14244篇
外科学   59348篇
综合类   904篇
现状与发展   75篇
一般理论   29篇
预防医学   14331篇
眼科学   6970篇
药学   13669篇
中国医学   1606篇
肿瘤学   22761篇
  2024年   750篇
  2023年   5642篇
  2022年   4186篇
  2021年   7922篇
  2020年   8220篇
  2019年   5470篇
  2018年   11324篇
  2017年   10452篇
  2016年   12458篇
  2015年   14101篇
  2014年   22093篇
  2013年   23507篇
  2012年   17854篇
  2011年   17399篇
  2010年   16940篇
  2009年   19747篇
  2008年   14160篇
  2007年   12044篇
  2006年   13738篇
  2005年   10487篇
  2004年   8893篇
  2003年   7144篇
  2002年   6570篇
  2001年   7183篇
  2000年   6140篇
  1999年   5639篇
  1998年   4655篇
  1997年   4238篇
  1996年   3981篇
  1995年   3756篇
  1994年   2403篇
  1993年   1972篇
  1992年   2278篇
  1991年   2271篇
  1990年   1831篇
  1989年   1839篇
  1988年   1599篇
  1987年   1464篇
  1986年   1314篇
  1985年   1176篇
  1984年   868篇
  1983年   780篇
  1982年   692篇
  1981年   600篇
  1980年   522篇
  1979年   581篇
  1978年   541篇
  1977年   534篇
  1975年   421篇
  1972年   428篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
Fast CT-PRESS-based spiral chemical shift imaging at 3 Tesla.   总被引:2,自引:0,他引:2  
A new sequence is presented that combines constant-time point-resolved spectroscopy (CT-PRESS) with fast spiral chemical shift imaging. It allows the acquisition of multivoxel spectra without line splitting with a minimum total measurement time of less than 5 min for a field of view of 24 cm and a nominal 1.5x1.5-cm2 in-plane resolution. Measurements were performed with 17 CS encoding steps in t1 (Deltat1=12.8 ms) and an average echo time of 151 ms, which was determined by simulating the CT-PRESS experiment for the spin systems of glutamate (Glu) and myo-inositol (mI). Signals from N-acetyl-aspartate, total creatine, choline-containing compounds (Cho), Glu, and mI were detected in a healthy volunteer with no or only minor baseline distortions within 14 min on a 3 T MR scanner.  相似文献   
13.
14.
Mutations in the gene encoding 11beta-hydroxysteroid dehydrogenase type 2, HSD11B2, cause a rare monogenic juvenile hypertensive syndrome called apparent mineralocorticoid excess (AME). In AME, defective HSD11B2 enzyme activity results in overstimulation of the mineralocorticoid receptor (MR) by cortisol, causing sodium retention, hypokalemia, and salt-dependent hypertension. Here, we have studied whether genetic variations in HDS11B2 are implicated in essential hypertension in Japanese hypertensives and the general population. By sequencing the entire coding region and the promoter region of HDS11B2 in 953 Japanese hypertensives, we identified five missense mutations in 11 patients (L14F, n = 5; R74H, n = 1; R147H, n = 3; T156I, n = 1; R335H, n = 1) and one novel frameshift mutation (4884Gdel, n = 1) in a heterozygous state, in addition to 19 genetic variations. All genetic variations identified were rare, with minor allele frequencies less than 0.005. Four of 12 patients with the missense/frameshift mutations showed renal failure. Four missense mutations, L14F, R74H, R147H, and R335H, were successfully genotyped in the general population, with a sample size of 3,655 individuals (2,175 normotensives and 1,480 hypertensives). Mutations L14F, R74H, R147H, and R335H were identified in hypertensives (n = 6, 8, 3, and 0, respectively) and normotensives (n = 8, 12, 5, and 0, respectively) with a similar frequency, suggesting that these missense mutations may not strongly affect the etiology of essential hypertension. Since the allele frequency of all of the genetic variations identified in this study was rare, an association study was not conducted. Taken together, our results indicate that missense mutations in HSD11B2 do not substantially contribute to essential hypertension in Japanese.  相似文献   
15.
16.
Although psychoanalysis was the first-choice treatment for premature ejaculation (PE) between 1920 and 1960, hardly any reports on its efficacy have been published. Moreover, a scientific debate about its findings has never been fully developed. The recent progress that has been made in the classification of three different PE syndromes creates a new opportunity for psychoanalytic investigations of men with complaints of PE, distinguished by the actual duration of their intravaginal ejaculation latency time (IELT). The term premature-like ejaculatory dysfunction has been introduced to distinguish men with self-perceived PE at normal and long IELT durations from those men with lifelong, acquired and normal variable PE. Psychoanalytic research may contribute to a better understanding of the consequences of objective early ejaculations on the unconscious mental life of men with the four forms of PE. By integrating neurobiological, clinical and epidemiological data of ejaculatory performance, a revival of psychoanalytic research of PE in the four distinct, classified PE groups, will probably contribute to a deeper insight in to the unconscious mental life of men affected by PE.  相似文献   
17.
18.
Fibromyalgia is a syndrome of widespread pain, nonrestorative sleep, disturbed mood, and fatigue. Optimal treatment involves a multidisciplinary approach with a team of health care providers using pharmacologic and nonpharmacologic treatment. Because of the heterogeneity of the illness, management should be individualized for the patient. Pharmacologic treatment should address issues of pain control, sleep disturbance, fatigue, and any underlying coexisting mood disorder. Nonpharmacologic treatment should include patient education, a regular exercise and stretching program, and cognitive behavioral therapy. All of these are essential to improving functional capacity and quality of life. This review provides general guidelines in initiating a successful pharmacologic treatment program for patients with fibromyalgia.  相似文献   
19.
20.
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