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   186425篇
  免费   13104篇
  国内免费   6521篇
耳鼻咽喉   1966篇
儿科学   3682篇
妇产科学   4966篇
基础医学   26752篇
口腔科学   4744篇
临床医学   18424篇
内科学   31894篇
皮肤病学   3174篇
神经病学   11561篇
特种医学   6371篇
外国民族医学   44篇
外科学   23590篇
综合类   16926篇
现状与发展   17篇
一般理论   36篇
预防医学   12860篇
眼科学   4610篇
药学   17357篇
  74篇
中国医学   4438篇
肿瘤学   12564篇
  2023年   1485篇
  2022年   3324篇
  2021年   4541篇
  2020年   3155篇
  2019年   3374篇
  2018年   3948篇
  2017年   3181篇
  2016年   3215篇
  2015年   4531篇
  2014年   5759篇
  2013年   5641篇
  2012年   8251篇
  2011年   9387篇
  2010年   5504篇
  2009年   4485篇
  2008年   6753篇
  2007年   7069篇
  2006年   7146篇
  2005年   6575篇
  2004年   5181篇
  2003年   4932篇
  2002年   4439篇
  2001年   8277篇
  2000年   8555篇
  1999年   7542篇
  1998年   3030篇
  1997年   2683篇
  1996年   1923篇
  1995年   1743篇
  1994年   1559篇
  1993年   1258篇
  1992年   4283篇
  1991年   4275篇
  1990年   3959篇
  1989年   3895篇
  1988年   3711篇
  1987年   3511篇
  1986年   3293篇
  1985年   3101篇
  1984年   2129篇
  1983年   1846篇
  1979年   1941篇
  1978年   1184篇
  1975年   1191篇
  1974年   1358篇
  1973年   1413篇
  1972年   1357篇
  1971年   1247篇
  1970年   1137篇
  1969年   1121篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
The distribution of tyrosine-hydroxylase (TH)-immunoreactive cell bodies and fibers in the diencephalon has been investigated with immunohistological techniques in the pigeon. The results suggest that TH is present in a number of morphologically distinct neuronal systems. Preoptic and hypothalamic TH neurons were subdivided into a medial periventricular and a lateral group. The medial group starts with a rostral collection of small cells in the preoptic region. A significantly larger collection of TH neurons occupies the paraventricular nucleus (PVN) (stratum cellulare internum) and mainly consists of large multipolar cells. Further caudally, the main concentration of cells is in the hypothalamic posteromedial and the periventricular regions of the tuberoinfundibular (arcuate) nucleus. No TH neuron was found in the ventral and lateral parts of the tuberoinfundibular region, suggesting that the prominent tuberoinfundibular dopaminergic system described in mammals is absent in the pigeon. This further substantiated by the relative scarcity of TH immunoreactive fibers and varicosities in the neurohemal zone of the median eminence (ME). The caudalmost components of the medial group appear to be continuous with the large population of TH neurons distributed in the midline of the mesencephalon. Tyrosine-hydroxylase-immunopositive cells have not been found in the paraventricular organ. The lateral group consists of TH neurons loosely arranged in the lateral hypothalamus, including regions of the supraoptic nucleus and hypothalamic posterolateral nucleus. Tyrosine-hydroxylase containing neurons vary widely in size, shape, and dendritic arborization in each diencephalic region. However, it is possible to distinguish two main cell types. Small bipolar neurons with two simple arborizing dendrites were concentrated in the medial periventricular system. The second type of cell is large, multipolar with four to five branching dendrites. This latter cell type occurs mainly in the lateral system and in the PVN. Major fiber bundles containing TH immunoreactivity were identified in the lateral and periventricular hypothalamus. The paraventricular organ and the organum vasculosum laminae terminalis contained the densest arborization of fibers and varicosities. In the ME, dense innervation was found in the subependymal layer. Dense arborizations of TH positive fibers and varicosities were located in the septal nuclei and the paleostriatum augmentatum.  相似文献   
102.
103.
Structure of receptive fields of visually sensitive neurons in areas CA1 and CA3 of the dorsal hippocampus was investigated in alert cats with the brain-stem pretrigeminal section. The receptive field (RF) structure of 76 hippocampal neurons was analyzed by methods of scanning the RF by moving stimuli and mapping all their surface by a stationary flashing spot. According to presented data the neurons were classified into three groups: neurons with homogeneous structure of the RF (54%), with nonhomogeneous (28%) and neurons more sensitive to stimulus motion (18%) than to a stationary flashing light. Experiments have shown that responses of hippocampal neurons are highly specific ones. Thus, 9% of neurons with the nonhomogeneous RF structure have shown specific responses to variation of the contrast and contours of moving stimuli. The presented results show that hippocampal visually driven neurons have well developed mechanism for processing visual sensory information and apparently this quality ensures participation of the limbic system in visually controlled behavior of the animal.  相似文献   
104.
The authors reviewed the radiographic manifestations of 17 cases of parosteal osteosarcoma, with pathologic correlation in 15. There were two types of parosteal osteosarcoma radiologically. The majority of cases were type I with uniformly dense masses which had regular borders. They often adhered to the cortex and showed no evidence of soft-tissue invasion which correlated with low-grade pathologic malignancy and a relatively benign clinical course. Type II involved the bone, soft-tissue and the medullary cavity. These lesions were poorly differentiated and frequently accompanied by metastatic lesions.
  相似文献   
105.
Sodium nucleinate, an officinal preparation (Na PHK), added to the growth medium in concentrations of 10 to 50 micrograms/ml enhanced the growth of hybridoma cells in vitro. Na PHK presence in the cultivation medium in the above concentrations enhanced the specific antibody-producing activity of hybridomas.  相似文献   
106.
The working clothes and individual protective devices recommended by the industrial Rules for the production of ampicillin trihydrate and its medicinal derivatives such as natrium salt ampicillin, do not provide adequate protection of the skin and respiratory mucous from antibiotic contamination. The use of the overalls in combination with the pressurized helmet (designed and produced at the 'Sintez' enterprise) which provided air supply for breathing and, partially, under the overalls, significantly decreased contamination of the body. At the stages of manual handling of the finished products, adequate protection was attained by using the protective paste produced at the 'Altaivitamine' enterprise.  相似文献   
107.
108.
随着"三医改革"的不断深入,医疗市场的竞争日趋激烈,人们对医院管理在生存和发展中的重要作用也日益关注.由于中医院面临着管理理念、资源优化、人才构筑和公平竞争的诸多问题,以往的经验管理已不能适应时代性、国际化的要求.面对瞬息万变的生存环境,需要各级中医医院能够主动参与竞争,充分发挥中医药特色,强化自身优势,对市场的变化迅速作出反应,这对中医医院管理工作提出了更高的要求.  相似文献   
109.
110.
PURPOSE: This study describes the prevalence of probable major depressive disorder (MDD) as well as other depressive disorders (ODD) and severity of depressive symptoms in a national sample of women with spinal cord injury (SCI) and compares them with a case-matched sample of men with SCI. METHODS: A sample of 585 women was drawn and case-matched with men from the SCI Model System National SCI Database according to level/completeness of injury, follow-up year, and age. The outcome measure of depression was the Patient Health Questionnaire. MAIN FINDINGS: Prevalence rates for women were 7.9% for probable MDD and 9.7% for ODD; rates for men were 9.9% and 10.3%, respectively. Logistic regression revealed that women who were divorced or at year 1 follow-up had a higher odds of having probable MDD (odds ratio [OR], 3.4 and 2.9, respectively). Employed women and men had significantly lower odds of probable MDD (OR, 0.274 and 0.358, respectively). Statistically significant differences were not found in gender comparisons for either probable MDD or symptom severity, which also were not associated with injury characteristics. CONCLUSION: The most significant, and unexpected, research finding is the absence of gender differences in probable MDD and symptom severity. Results challenge notions that depression will necessarily follow SCI; that injury characteristics determine the development and severity of depression; and that women experience a greater burden of depression than men. The main clinical implication is that depression screening and referral should be a routine feature of health care for women living with SCI, as well as for their male counterparts. Furthermore, nearly one fourth of women and men reported experiencing some or greater difficulty in daily life and relationships in the absence of probable depressive disorder, warranting monitoring of subsyndromal depression as well.  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