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   17132篇
  免费   1562篇
  国内免费   18篇
耳鼻咽喉   152篇
儿科学   630篇
妇产科学   578篇
基础医学   2320篇
口腔科学   363篇
临床医学   1825篇
内科学   2927篇
皮肤病学   218篇
神经病学   1810篇
特种医学   877篇
外科学   2114篇
综合类   334篇
一般理论   21篇
预防医学   1890篇
眼科学   333篇
药学   1369篇
中国医学   19篇
肿瘤学   932篇
  2021年   235篇
  2020年   187篇
  2019年   220篇
  2018年   279篇
  2017年   238篇
  2016年   235篇
  2015年   280篇
  2014年   375篇
  2013年   532篇
  2012年   767篇
  2011年   787篇
  2010年   477篇
  2009年   384篇
  2008年   715篇
  2007年   728篇
  2006年   694篇
  2005年   660篇
  2004年   593篇
  2003年   628篇
  2002年   567篇
  2001年   546篇
  2000年   546篇
  1999年   495篇
  1998年   207篇
  1997年   181篇
  1996年   157篇
  1995年   151篇
  1994年   136篇
  1992年   390篇
  1991年   411篇
  1990年   409篇
  1989年   363篇
  1988年   388篇
  1987年   396篇
  1986年   321篇
  1985年   346篇
  1984年   264篇
  1983年   223篇
  1982年   142篇
  1979年   252篇
  1978年   194篇
  1977年   142篇
  1976年   167篇
  1974年   178篇
  1973年   170篇
  1972年   151篇
  1971年   139篇
  1970年   135篇
  1969年   169篇
  1968年   146篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
We report an analysis of the qualitative phase of a study of patients' and carers' views of primary care services, focusing on their experiences of access to face-to-face general practitioner (GP) consultations during the period when new access policies were being implemented. Practices interpreted the new policy in various ways; restricted interpretations, including restriction of access to telephone booking, could cause distress to patients. Patients and carers welcomed flexible interpretations of the policy that offered choice, such as a choice of GP, or of booking in advance.  相似文献   
33.
34.
Summary: Some of the properties of 4–bromobenzalde-hyde semicarbazone (compound IV), a prototype molecule of a new class of anticonvulsants, aryl semicarbazones, are described. Compound IV demonstrated activity in the maximal electroshock (MES) and subcutaneous pentylenetetrazol (scPTZ) tests in mice, with low neurotoxicity. When given orally to rats, it displayed high potency in the MES test and very low neurotoxicity, resulting in a high protective index (PI). Compound IV displayed no proconvulsant properties, and development of rapid tolerance was not noted. When administered intraperitoneally (i.p.) at doses of 100, 300, or 600 mg/kg to rats, compound IV had no effect on levels of γ-aminobu-tyric acid (GABA) or on GABA-T activity in whole brain. When tested in vitro, compound IV had no effect on rat brain GABA-T at a drug concentration of 100 μM. Although the activities of certain drug-metabolizing enzymes were increased after oral administration of compound IV to rats, these effects were less prominent than those of phenytoin (PHT) and carbamazepine (CBZ). The principal mode of action of compound IV does not appear to be an interaction with the GABAA receptor complex, and other mechanisms, involving excitatory amino acid neurotransmission, will have to be considered in future investigations of the anticonvulsant activity of this compound.  相似文献   
35.
To determine whether pulsatile hypothermic perfusion with University of Wisconsin preservation solution is superior to topical cooling as a method for the preservation of amputated limbs, six pairs of amputated canine limbs were preserved for twelve to fifteen hours. One limb of each pair was subjected to topical cooling and the other, to pulsatile hypothermic perfusion with University of Wisconsin solution. The bioenergetic status of the limbs was monitored by 31phosphorus magnetic-resonance spectroscopy, and histological evaluation was performed to assess ischemic changes in the preserved tissue. The pH and tissue levels of adenosine triphosphate declined three times more slowly in the limbs that were preserved by pulsatile hypothermic perfusion than in the topically cooled limbs. Consistent with these findings, the perfused limbs also had less histological evidence of ischemic injury. The data from this in vitro study show that pulsatile hypothermic perfusion with University of Wisconsin solution, in combination with an optimum degree of topical cooling, is superior to topical cooling alone as a method of preserving the bioenergetic status of amputated limbs.  相似文献   
36.
Thirty-two stage IC or stage I grade 3 patients with invasive ovarian adenocarcinoma were treated with 6 months of adjuvant cisplatin-based chemotherapy. With a median follow-up of 60.5 months, there have been three (9%) recurrences. The 5-year progression-free survival was 90.5% and the 5-year survival was 93.3%.  相似文献   
37.
Adult supraglottitis. A prospective analysis   总被引:1,自引:0,他引:1  
J Shapiro  R D Eavey  A S Baker 《JAMA》1988,259(4):563-567
  相似文献   
38.
The aim of this study was to explore undergraduate and postgraduate dental students' understanding of a good learning experience by using 'reflection on learning' as described by Schon. Four groups of Year 4 BDS students and one group of postgraduate students in dental public health took part in a series of focus group discussions. The responses were grouped into four broad themes (a) active, practical and positive learning; (b) interactive/together learning; (c) personal learning; (d) theory into practice. Six educational models of good learning proposed by the students are described.  相似文献   
39.
Glycinebetaine has previously been shown to be effective at reducing leakage from liposomes which are frozen then thawed. This study involved the preparation of a series of N-modified betaines and the comparison of their cryoprotective activities with those of glycine, sarcosine, N,N-dimethylglycine and glycinebetaine. All the compounds investigated, with the exception of (dimethyloctylammonio)acetate, reduced the degree of leakage, after freezing and thawing, with additive concentrations up to 0.6 M. Reducing the degree of N-terminal methylation of glycinebetaine appeared to increase the leakage from liposomes at additive concentrations between 0.2 and 0.6 M. (Dimethylethylammonio)acetate, (dimethylisopropylammonio)acetate and (N,N,N',N'-tetramethylethylenediammonio)-N,N'-diacetate appeared to be no more effective than glycinebetaine, whereas improved protection was afforded by (triethylammonio)acetate and (diethylmethylammonio)acetate at most concentrations. This study demonstrates that the cryoprotective activity of glycinebetaine may be improved with modifications to the N-terminal.  相似文献   
40.
Summary: We have been involved in developing a health-related quality-of-life model for use as an outcome measure in epilepsy. As part of the further development of this model, we have developed a measure of life fulfilment. This scale is based on methods previously described by Krupinski in 1980. The value of Krupinski's approach is the opportunity for patients to weight the numerous aspects of their quality of life and assess the discrepancy between their actual and desired circumstances. The life fulfilment scale has been shown to be reliable (α= 0.7) and valid. The scale is currently being applied to several clinical studies in epilepsy. We believe that the scale provides a valuable contribution to our health-related quality-of-life model.  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