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   1142686篇
  免费   82574篇
  国内免费   2924篇
耳鼻咽喉   15043篇
儿科学   38678篇
妇产科学   31913篇
基础医学   166209篇
口腔科学   32556篇
临床医学   98753篇
内科学   226160篇
皮肤病学   26917篇
神经病学   90876篇
特种医学   41922篇
外国民族医学   305篇
外科学   166537篇
综合类   24442篇
一般理论   408篇
预防医学   95419篇
眼科学   26527篇
药学   83185篇
  3篇
中国医学   2610篇
肿瘤学   59721篇
  2021年   9099篇
  2019年   9880篇
  2018年   15064篇
  2017年   11014篇
  2016年   12119篇
  2015年   13676篇
  2014年   17765篇
  2013年   27166篇
  2012年   38105篇
  2011年   40422篇
  2010年   23209篇
  2009年   20871篇
  2008年   36656篇
  2007年   38923篇
  2006年   39120篇
  2005年   37404篇
  2004年   36161篇
  2003年   34621篇
  2002年   33274篇
  2001年   51114篇
  2000年   52755篇
  1999年   43876篇
  1998年   11810篇
  1997年   10478篇
  1996年   10536篇
  1995年   10113篇
  1994年   9377篇
  1992年   34173篇
  1991年   33212篇
  1990年   32737篇
  1989年   31349篇
  1988年   28596篇
  1987年   28639篇
  1986年   26800篇
  1985年   25875篇
  1984年   19296篇
  1983年   16303篇
  1982年   9682篇
  1979年   17922篇
  1978年   12904篇
  1977年   10987篇
  1976年   10390篇
  1975年   10939篇
  1974年   13316篇
  1973年   12886篇
  1972年   11873篇
  1971年   11074篇
  1970年   10264篇
  1969年   9681篇
  1968年   9073篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
A number of neurotransmitters and neuropeptides in the hypothalamus play a role in the control of food intake, metabolism, and body weight. Particularly, noradrenergic mechanisms in several areas of the hypothalamus are involved. Control of peripheral metabolism by the hypothalamus is achieved via autonomic modulation of the function of hepatocytes, adipocytes, and the endocrine cells in the islets of Langerhans. The autonomic control mechanisms ultimately lead to an appropriate shaping of blood glucose, plasma FFA, and insulin profiles to guarantee an adequate flow of nutrients under different physiological situations. Peripheral insulin and glucose can penetrate into the brain where they might affect the function of those brain structures involved in control of food intake, metabolism, and body weight.  相似文献   
993.
A quantitative assay for ALZ-50 immunoreactivity was evaluated in samples of superior temporal gyrus taken at autopsy from 13 Alzheimer patients and 11 controls. The assayable immunoreactivity appears to be stable for at least 24 hours postmortem but was lost with formalin fixation. The mean value of the Alzheimer patients was tenfold higher than that of the controls (P less than .002). The values of four Alzheimer samples overlapped with the low levels seen in controls, but no controls had elevated levels. In this sample population, therefore, the assay had a sensitivity of 69% and specificity of 100%.  相似文献   
994.
This series of articles, Managing Your Academic Career, presents ways to intentionally improve your teaching. This first article explains the concept of becoming an intention teacher. Subsequent articles will deal with strategies that are useful in clinical teaching, such as preparing students to value and use research in practice, and providing feedback to students in the clinical setting.  相似文献   
995.
996.
Single or combined monoclonal antibodies (McAbs) Zh53, Zh820, and Zh2-1 have been used to eliminate malignant clonogenic cells from human bone marrow. The test of cytotoxicity showed that all of these McAbs could express high specific cytotoxic action against HL-60 cells and were selectively complement-dependent cytotoxic to various types of fresh leukemic cells. Clonogenic assay detected that single treatment with antibody and rabbit complement (RC) could reduce clonogenic units of HL-60 cells by more than 2 logs and two treatments reduced clonogenic units by more than 4 logs. However, combination of 2 McAbs could reduce clonogenic units by 4-5 logs. The data suggest that multiple treatments with McAbs and RC or a combination of 2 McAbs are more effective than a single treatment in eliminating clonogenic tumor cells. Treatment of normal human bone marrow with Zh53, Zh2-1 and RC did not produce a loss of normal CFU-GM, but treatment with Zh820 reduced the clonic units of normal CFU-GM by 24%.
  相似文献   
997.
998.
We studied the relationship between arterial carbon dioxide tension (PaCO2) and fresh gas flow (FGF) during use of the Bain breathing circuit for Caesarean section anaesthesia. Thirty-one patients undergoing Caesarean section were anaesthetised using the Bain circuit with intermittent positive pressure ventilation. The PaCO2 were measured at FGF of 70 ml X kg-1 X min-1, 80 ml X kg-1 X min-1, and 100 ml X kg-1 X min-1. The FGF requirement to maintain a given PaCO2 during Caesarean section anaesthesia is the same as the requirements for nonpregnant subjects, despite the increase in carbon dioxide production associated with pregnancy. This is probably because the total FGF determined by body weight and given during Caesarean section anaesthesia is 15-20 per cent higher than nonpregnant levels, due to the weight gain associated with pregnancy. A FGF of 100 ml X kg-1 of pregnant weight/min maintains PaCO2 of 4.44 kPa predelivery, which is in the desirable range of PaCO2 during Caesarean section.  相似文献   
999.
Spinal opiate analgesia has opened an exciting new field of research and has also rapidly gained widespread clinical acceptance. This mode of administration has obvious and definite advantages over conventional pain therapy; however, the field is still at an early stage of development. More research is clearly needed to provide methods for coping with some of the drawbacks of this method of pain relief. Important areas for future research include (1) the CSF kinetics of opiates; (2) the physiological mechanisms underlying the rostral spread of drugs within the CSF compartment; (3) a search for safer and more selective drugs; and (4) an evaluation of the extent to which pain-modulating systems at different levels in the CNS can be regulated by opiates and drugs interfering with other neurotransmitters. In this context it is essential to emphasize the importance of simultaneous study of the pharmacokinetics and the pharmacodynamic/clinical effects in providing a rational basis for a better understanding of the mechanisms of actions underlying spinal opiate analgesia.  相似文献   
1000.
We report 2 cases of diffuse intraperitoneal metastases from testicular carcinoma following transabdominal retroperitoneal lymphadenectomy. This is an unusual pattern of metastasis for nonseminomatous germ cell tumors and it is believed to be the result of direct seeding from lymphatic leakage secondary to surgery. The value of computerized tomography in diagnosing this entity is emphasized.  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