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   119119篇
  免费   6949篇
  国内免费   1582篇
耳鼻咽喉   1575篇
儿科学   2971篇
妇产科学   4109篇
基础医学   18326篇
口腔科学   3617篇
临床医学   9287篇
内科学   21795篇
皮肤病学   2437篇
神经病学   8017篇
特种医学   4023篇
外国民族医学   3篇
外科学   16768篇
综合类   5217篇
一般理论   34篇
预防医学   8686篇
眼科学   2818篇
药学   10205篇
中国医学   818篇
肿瘤学   6944篇
  2021年   988篇
  2019年   1048篇
  2018年   1615篇
  2017年   1167篇
  2016年   1201篇
  2015年   1445篇
  2014年   1887篇
  2013年   2449篇
  2012年   3560篇
  2011年   3810篇
  2010年   2303篇
  2009年   2060篇
  2008年   3392篇
  2007年   3638篇
  2006年   3622篇
  2005年   3193篇
  2004年   2989篇
  2003年   2777篇
  2002年   2634篇
  2001年   6739篇
  2000年   6926篇
  1999年   5704篇
  1998年   1833篇
  1997年   1379篇
  1996年   938篇
  1995年   863篇
  1992年   3730篇
  1991年   3811篇
  1990年   3549篇
  1989年   3553篇
  1988年   3431篇
  1987年   3278篇
  1986年   3093篇
  1985年   2967篇
  1984年   2049篇
  1983年   1794篇
  1982年   985篇
  1979年   1910篇
  1978年   1184篇
  1977年   986篇
  1976年   919篇
  1975年   1192篇
  1974年   1363篇
  1973年   1414篇
  1972年   1358篇
  1971年   1249篇
  1970年   1142篇
  1969年   1121篇
  1968年   1029篇
  1967年   897篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
The effect of ferritins from horse (FH) and bovine (FB) spleen and murine liver (FM) on the survival rate of CFW mice lethally infected with Escherichia coli (strain 8440-78 K 80/B) was evaluated. Ferritins given intravenously 24 h before intravenous inoculation of bacteria, protected mice most effectively from death due to infection. The effect was dose dependent. At 500 micrograms of ferritin per mouse, the maximum survival rates were 86% (FH), 81% (FM) and 79% (FB), while only 5% of the control mice survived up to the 30th day. The survival rates of animals injected with bovine serum albumin (BSA) and heat-inactivated FB were 8 and 25%, respectively. Intraperitoneal injection of FB was as effective as intravenous in enhancing the resistance of mice against bacteria. These data provide evidence for the beneficial role of tissue ferritins in nonspecific antibacterial resistance.  相似文献   
72.
73.
74.
75.
76.
Previous pharmacological studies with the pituitary gland have suggested that acetylcholine (ACh) might be involved in the regulation of intermediate lobe (IL) function. Whether ACh is endogenous to the IL cells or provided from an extrinsic source is unclear. The present experiments tested the possibility that the endocrine cells of the IL may be a source of ACh by measuring certain cholinergic markers in a primary culture of dissociated porcine cells. The endogenous ACh content was readily measurable in both the freshly dissociated IL cells and in 2- or 4-day primary cultures. Choline acetyltransferase activity was also measurable in the freshly dissociated and cultured IL cells and was reduced by 53% in the presence of a specific inhibitor, napthylvinylpyridine (50 μM). IL cells incubated in the presence of [14C]choline (1 μM) were able to synthesize [14C]ACh and the accumulation of the new ACh was inhibited by hemicholinium-3 (30 μM), a competitive inhibitor of high affinity choline uptake at cholinergic nerve terminals. In conclusion, these results demonstrate that the endocrine cells of the IL are capable of synthesizing and storing ACh.  相似文献   
77.
78.
79.
Periodic, lateralized, epileptiform discharges (PLEDs) in the electroencephalogram have been reported in association with a variety of structural lesions of the brain. Although a great deal of attention has been directed to the neuropathological basis of PLEDs, little emphasis has been placed on the functional basis of this EEG syndrome. In this paper, we reported a patient with multiple systemic problems whose EEG showed PLEDs. However, radiological and pathological studies revealed no neuropathological basis for the occurrence of this EEG syndrome. Thus, we presented evidence that metabolic factors may play a part in the pathogenesis of PLEDs.  相似文献   
80.
Previously we have shown that the dorsal lateral geniculate body (LGB), which is strictly visual in sighted mammals, receives a strong auditory input in the naturally blind mole rat (Spalax ehrenbergi). Here we show with the 2-deoxyglucose technique and with single-unit recordings that in this species the initially non-degenerated visual cortex, as defined by its connection with LGB, is also activated by the auditory modality. These findings suggest that cross-modal compensation may occur as a natural consequence of the degeneration of a sense organ.  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