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   210299篇
  免费   15230篇
  国内免费   749篇
耳鼻咽喉   2286篇
儿科学   5484篇
妇产科学   4304篇
基础医学   27125篇
口腔科学   4512篇
临床医学   19999篇
内科学   44887篇
皮肤病学   2754篇
神经病学   20306篇
特种医学   6951篇
外国民族医学   13篇
外科学   32932篇
综合类   3411篇
现状与发展   2篇
一般理论   291篇
预防医学   19063篇
眼科学   4373篇
药学   14387篇
  1篇
中国医学   374篇
肿瘤学   12823篇
  2023年   843篇
  2022年   1406篇
  2021年   3446篇
  2020年   2109篇
  2019年   3391篇
  2018年   3969篇
  2017年   3215篇
  2016年   3412篇
  2015年   4068篇
  2014年   6098篇
  2013年   8825篇
  2012年   13128篇
  2011年   14326篇
  2010年   8097篇
  2009年   7307篇
  2008年   13591篇
  2007年   14425篇
  2006年   13921篇
  2005年   14394篇
  2004年   13808篇
  2003年   12900篇
  2002年   12436篇
  2001年   1873篇
  2000年   1459篇
  1999年   2045篇
  1998年   2828篇
  1997年   2437篇
  1996年   2206篇
  1995年   1954篇
  1994年   1755篇
  1993年   1655篇
  1992年   1208篇
  1991年   1150篇
  1990年   1053篇
  1989年   952篇
  1988年   1011篇
  1987年   1019篇
  1986年   998篇
  1985年   1081篇
  1984年   1478篇
  1983年   1461篇
  1982年   1814篇
  1981年   1639篇
  1980年   1555篇
  1979年   812篇
  1978年   958篇
  1977年   932篇
  1976年   831篇
  1975年   682篇
  1974年   666篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
This paper is about developing work with young men within an existing clinic for young women. The experience was very new for the young men who attended, often in groups, and some staff considered them to be disruptive and troublesome. In order to meet young men's needs, staff need a different kind of training, and services have to develop a broader sense of sexual health. This means an approach that is less medical and instead offers more support and advice.  相似文献   
82.
There are conflicting reports on the relationship between cerebellar vermal lobule hypoplasia and autism. Using quantitative magnetic resonance image analysis, we measured the cerebellar vermis in 125 normal individuals with a broad age range and 102 patients with a variety of neurogenetic abnormalities. We conclude that hypoplasia of cerebellar vermal lobules VI and VII is a nonspecific finding that even occurs in several conditions without autistic behavior. This suggests that it is not a specific neuroanatomical marker for autism, nor is cerebellar dys- genesis likely to be solely responsible for clinical autistic behaviors.  相似文献   
83.
84.
85.
86.
A range of 18 derivatives of flavone-8-acetic acid (FAA) with substituents on the 2-phenyl group have been prepared and their anti-tumour activity evaluated in vitro against a panel of human and murine tumour cell lines and in vivo against MAC 15A. There was no clear-cut relationship between in vitro and in vivo activity but the activity in each situation was found to be very sensitive to the precise substitution pattern with closely related isomers giving widely different activities. Some of the compounds, notably 10b,cj , and r , were active in vivo and these require further studies in order to evaluate their potential for development.  相似文献   
87.
The development of intrinsic, N-methyl-D-aspartate (NMDA) receptor-mediated voltage oscillations and their dependence on co-activation of 5-hydroxytryptamine (5HT) receptors was explored in motor neurons of late embryonic and early larval Xenopus laevis. Under tetrodotoxin, 100 μM NMDA elicited a membrane depolarization of around 20 mV, but did not lead to voltage oscillations. However, following the addition of 2–5 μM 5HT, oscillations were observed in 12% of embryonic and 70% of larval motor neurons. The voltage oscillations depended upon co-activation of NMDA and 5HT receptors since they were curtailed by selectively blocking NMDA receptors with D-2-amino-5-phosphonovaleric acid (APV) or by excluding Mg2+ from the experimental saline. 5HT applied in the absence of NMDA also failed to elicit oscillations. Oscillations could be induced by the non-selective 5HT1a receptor agonist, 5-carboxamidotryptamine (5CT) and both 5HT- and 5CT-induced oscillations were abolished by pindobind-5HT1, a selective 5HT1a receptor antagonist. To test whether 5HT enables voltage oscillations by modulating the voltage-dependent block of NMDA channels by Mg2+, membrane conductance was monitored under tetrodotoxin. Although 5HT caused membrane hyperpolarization of 4–8 mV, there was little detectable change in conductance. NMDA application caused an approximate 20 mV depolarization and an ‘apparent’ decrease in conductance, presumably due to the conductance pulse bringing the membrane into a voltage region where Mg2+ blocks the NMDA ionophore. 5HT further decreased conductance, which we propose is due to its enhancement of the voltage-dependent Mg2+ block. When the membrane potential was depolarized by ~20 mV via depolarizing current injection (to mimic the NMDA-induced depolarization), 5HT increased rather than decreased membrane conductance. Furthermore, 5HT did not affect the increase in membrane conductance following NMDA applications in zero Mg2+ saline. The results suggest that intrinsic, NMDA receptor-mediated voltage oscillations develop in a brief period after hatching, and that they depend upon the co-activation of 5HT and NMDA receptors. The enabling function of 5HT may involve the facilitation of the voltage-dependent block of the NMDA ionophore by Mg2+ through activation of receptors with 5HT1a-like pharmacology.  相似文献   
88.
89.
90.
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