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   19248篇
  免费   3417篇
  国内免费   149篇
耳鼻咽喉   480篇
儿科学   503篇
妇产科学   524篇
基础医学   1794篇
口腔科学   369篇
临床医学   4028篇
内科学   3632篇
皮肤病学   491篇
神经病学   1369篇
特种医学   691篇
外科学   2568篇
综合类   574篇
现状与发展   2篇
一般理论   5篇
预防医学   2724篇
眼科学   253篇
药学   1041篇
  1篇
中国医学   109篇
肿瘤学   1656篇
  2024年   85篇
  2023年   444篇
  2022年   168篇
  2021年   391篇
  2020年   579篇
  2019年   299篇
  2018年   719篇
  2017年   719篇
  2016年   765篇
  2015年   845篇
  2014年   913篇
  2013年   1354篇
  2012年   849篇
  2011年   813篇
  2010年   775篇
  2009年   869篇
  2008年   695篇
  2007年   667篇
  2006年   741篇
  2005年   627篇
  2004年   598篇
  2003年   537篇
  2002年   500篇
  2001年   557篇
  2000年   542篇
  1999年   494篇
  1998年   387篇
  1997年   416篇
  1996年   431篇
  1995年   343篇
  1994年   256篇
  1993年   212篇
  1992年   365篇
  1991年   349篇
  1990年   287篇
  1989年   303篇
  1988年   290篇
  1987年   256篇
  1986年   226篇
  1985年   215篇
  1984年   175篇
  1983年   172篇
  1982年   119篇
  1981年   132篇
  1980年   92篇
  1979年   147篇
  1978年   97篇
  1977年   100篇
  1976年   96篇
  1974年   104篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Parasellar syndrome caused by plasma cell leukemia   总被引:1,自引:0,他引:1  
A 71-year-old man had incomplete third cranial nerve palsy caused by plasma cell leukemia and a parasellar plasmacytoma. This is the first reported case of plasma cell leukemia in which a central nervous system sign was the initial manifestation. Only one previous case of intracranial plasmacytoma associated with plasma cell leukemia has been reported. The characteristics of intracranial plasmacytomas and of plasma cell leukemia are discussed.  相似文献   
62.
63.
64.
Approximately 11,550 women with epilepsy give birth annually, yet maternity nurses receive little information on how to care for these patients. Children of epileptic mothers are born with an increased incidence of birth defects, and have a higher perinatal mortality rate. Complications such as bleeding during pregnancy, and interventions such as cesarean births and labor inductions are more common among epileptic women, and seizures tend to increase during pregnancy in more than one-third of epileptic women. Informed nursing care is essential to ensure the best possible outcome of these pregnancies.  相似文献   
65.
66.
Exposure of murine erythroleukemia cells (MELCs) to nicotinamide (NA) or its synthetic analog N′-methylnicotinamide (N′-MN) reduces cell growth and induces terminal differentiation, marked by increased heme and globin accumulation. On the contrary, 1-methylnicotinamide (1-MN), the primary metabolite of excess NA, was found to stimulate cell growth and reduce spontaneous differentiation of cultured MELCs. Log phase MELCs exhibited up to 50% higher cell density above untreated cells when cultured for up to 96 h with 2.5 mM 1-MN. When combined with NA or several chemically-unrelated inducers of hemoglobin synthesis in cultured MELCs, 1-MN reduced the globin mRNA levels and heme accumulation by 40–80%. 1-MN was able to inhibit heme production if present during only the first 24–48 h after NA exposure. Pre-treatment with 1-MN could not confer resistance of cells to effects of NA, suggesting the inhibition is reversible. Commitment to differentiate in semisolid medium by the most potent inducer, 5 mM N′-MN, was inhibited up to 95% by 2.5 mM concentrations of 1-MN. It appears that 1-MN has opposing effects on growth and induction of differentiation than those seen in MELC cultures exposed to NA or N′-MN.  相似文献   
67.
AIM: The aim of this study was to investigate the nature and organization of maternal needs and priorities in a neonatal unit. BACKGROUND: The relationship between maternal needs and priorities appears to be an under studied area in neonatal nursing. METHODS: A quantitative survey was carried out based on 209 mothers with premature infants. Two self-assessment schedules were used: critical care maternal needs inventory (J. Leske, Heart and Lung 15, 27-42) and a ranking scale. The data were analysed with multivariate analysis. FINDINGS: Data analysis revealed clear priorities in maternal needs. In particular the need for accurate infant related information was a priority for 93% of the mothers. Good communication practices with professionals were also valued. The mothers displayed altruistic behaviour, and self-related needs took second place. It is proposed that maternal needs demonstrate a hierarchical organization. CONCLUSION: It is important for nurses to consider the individual needs of the mothers, simply because the satisfaction of these needs is essential for maternal well-being.  相似文献   
68.
69.
Clinical utilisation of positron emission tomography could be enhanced by the availability of short-lived radionuclides derived from generator systems. The zinc-62/copper-62 combination is one such system which could be used as a source for a number of copper-62 radiopharmaceuticals. We have developed and optimised a high activity (5.6 GBq, 150 mCi) zinc-62/copper-62 generator to provide 62Cu in a form that is suitable for direct labelling of pyruvaldehyde-bis-(N4-methylthiosemicarbazone)-copper(II), Cu(PTSM). The distribution coefficients of Zn(II) and Cu(II) between anion-exchange resin and various hydrochloric acid/organic solvent mixtures were measured. Based on these measurements a generator eluent of 0.3 M HCl/40% ethanol provided 62Cu in greater than 90% yield in a 3-ml volume. A very low 62Zn breakthrough of less than 3 x 10(-7)% was achieved. Copper-PTSM was successfully labelled with the no-carrier-added 62Cu eluent directly from the generator with 94% radiochemical yield.  相似文献   
70.
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