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   2694228篇
  免费   205191篇
  国内免费   8508篇
耳鼻咽喉   34989篇
儿科学   88320篇
妇产科学   73257篇
基础医学   376091篇
口腔科学   76458篇
临床医学   243787篇
内科学   535854篇
皮肤病学   62581篇
神经病学   214880篇
特种医学   105113篇
外国民族医学   505篇
外科学   413476篇
综合类   63836篇
现状与发展   6篇
一般理论   904篇
预防医学   208081篇
眼科学   61602篇
药学   193700篇
  11篇
中国医学   5920篇
肿瘤学   148556篇
  2018年   29376篇
  2017年   22570篇
  2016年   25667篇
  2015年   29096篇
  2014年   40532篇
  2013年   60258篇
  2012年   79094篇
  2011年   84153篇
  2010年   51042篇
  2009年   48494篇
  2008年   78198篇
  2007年   83332篇
  2006年   84611篇
  2005年   81294篇
  2004年   78153篇
  2003年   74997篇
  2002年   71883篇
  2001年   134637篇
  2000年   138260篇
  1999年   114695篇
  1998年   32247篇
  1997年   28426篇
  1996年   29162篇
  1995年   28672篇
  1994年   26525篇
  1993年   24701篇
  1992年   90710篇
  1991年   87945篇
  1990年   84826篇
  1989年   81322篇
  1988年   74713篇
  1987年   73342篇
  1986年   69094篇
  1985年   66075篇
  1984年   49566篇
  1983年   41848篇
  1982年   24804篇
  1981年   22261篇
  1980年   20603篇
  1979年   44087篇
  1978年   31233篇
  1977年   26604篇
  1976年   24614篇
  1975年   25783篇
  1974年   30745篇
  1973年   29622篇
  1972年   27504篇
  1971年   25316篇
  1970年   23377篇
  1969年   21925篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
The ratio of growth hormone response to clonidine and L-dopa challenge was compared in 74 boys: 15 with purported physical abuse, 7 with purported sexual abuse, 13 normal controls, and 39 psychiatric controls. Sexually abused boys demonstrate a statistically significant elevated ratio of growth hormone response to clonidine versus response to L-dopa. Physically abused boys demonstrate lower clonidine/L-dopa growth hormone response ratios compared with controls. These effects widen with increasing physical development.  相似文献   
962.
A serotonin (5-HT)-mediated phosphoinositide hydrolysis response was characterized in fibroblasts cultured from rabbit choroid plexus. 5-HT elicited a maximum 8-fold increase in [3H]inositol-phosphate ([3H]IP) formation, while the partial agonists, (+)-lysergic acid diethylamide and (−)-1-(4-bromo-2,5-dimethyoxyphenyl)-2-aminopropane caused 2- and 5-fold increases, respectively. Mianserin, ketanserin, and spiperone were equipotent at blocking the 5-HT-mediated response. Thus, agonist and antagonist profiles indicate interactions with 5-HT2 receptors.  相似文献   
963.
Three children with malignant primary CNS tumors treated with craniospinal radiotherapy developed intraparenchymal hemorrhages a median of 5 years following therapy in sites distant from the primary tumor. Radical surgical procedures disclosed fresh and old hematoma, gliosis, and necrosis in all 3 patients and an aggregation of abnormal microscopic blood vessels in two. No tumor was found. All 3 patients remain in long-term (greater than 10 years) continuous remission.  相似文献   
964.
The erythrocyte membrane transports (MT) of L-tyrosine and L-tryptophan, as well as their plasma levels, were measured in 143 depressed patients after a wash-out period of one week and before any antidepressant treatment, and then at regular intervals until they recovered. 49 normal subjects served as a control group. The perturbations of these biologic variables at baseline were different according to diagnostic groups (DSM III), compared to controls: significant decrease of the two MT in depressed bipolar disorders; significant decrease of MT in depressed bipolar disorders; significant decrease of MT tyrosine and significant increase of MT tryptophan in recurrent major depressions; no significant changes of MT in dysthymic disorders. The plasma levels of tyrosine and total tryptophan show a significant diminution in the 3 groups. The study of the evolution of these same variables after antidepressant treatment show a return to normal of the MT at recovery, as well as the plasma levels of tyrosine. The plasma levels of tryptophan stay low in depressed bipolar disorders and recurrent major depressions.  相似文献   
965.
966.
967.
968.
Nurses have a long history of caring for clients with chronic mental illness. A primary treatment modality used with these clients is supportive psychotherapy. Often this approach is not well understood, even by those who purport to practice it. While supportive therapy tends not to enjoy the prestige associated with other forms of individual psychotherapy, the author contends that supportive psychotherapy can be an interesting and challenging treatment modality for working with clients with chronic mental illness.  相似文献   
969.
A seven-month-old girl with atypical West syndrome with pedaling automatism was reported. She started to have early infantile epileptic encephalopathy with suppression-burst (EIEE) at age 14 days followed by infantile spasms at 3 months of age. She began to have spasms with automatism at 4 month, mainly consisting of pedaling movements of both feet associated with tonic spasms of upper extremities and writhing of trunk. Ictal EEG showed irregular slow waves with occasional spikes predominantly over the right hemisphere mixed with artifacts. Interictal EEG during sleep showed suppression-burst patterns. Cerebral atrophy and microcephaly were revealed on brain CT, immature myelination on MRI and decreased blood flow in the frontal, temporal, and parietal lobes on the right on PET scan. Pedaling automatism is rare in infancy and its clinical significance was discussed in relation to West syndrome and complex partial seizures.  相似文献   
970.
Pattern visual evoked potentials were obtained from 46 patients with definite relapsing/remitting multiple sclerosis, using both a conventional 5-channel occipital array and a 3-D recording technique consisting of three bipolar derivations approximating the three dimensions of space. These three orthogonal wave forms were displayed as a 3-D Lissajous trajectory for each subject. Two of the 15 patients with completely normal conventional pattern VEPs had abnormalities of the orientation of the B-C curvilinear segment of the 3-D pattern VEPs. Delays in the first major occipital positive component (P100) were evident using both techniques; the correlation between P100 latency and the latency of the corresponding trajectory apex was r = 0.99 (P less than 0.01). Post-chiasmal MRI abnormalities were associated with 3-D VEP orientation abnormalities. Three-dimensional pattern VEPs are moderately more sensitive than conventional pattern VEPs at detecting dysfunction posterior to the optic chiasm in demyelinating disease and do not require the use of eccentric fixation to do so.  相似文献   
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