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   10845篇
  免费   671篇
  国内免费   55篇
耳鼻咽喉   70篇
儿科学   313篇
妇产科学   284篇
基础医学   1164篇
口腔科学   429篇
临床医学   1219篇
内科学   1933篇
皮肤病学   126篇
神经病学   891篇
特种医学   529篇
外科学   1427篇
综合类   675篇
一般理论   11篇
预防医学   1126篇
眼科学   205篇
药学   647篇
  3篇
中国医学   101篇
肿瘤学   418篇
  2021年   165篇
  2020年   98篇
  2019年   136篇
  2018年   139篇
  2017年   139篇
  2016年   135篇
  2015年   167篇
  2014年   222篇
  2013年   348篇
  2012年   515篇
  2011年   525篇
  2010年   323篇
  2009年   298篇
  2008年   491篇
  2007年   522篇
  2006年   494篇
  2005年   472篇
  2004年   414篇
  2003年   365篇
  2002年   377篇
  2001年   328篇
  2000年   317篇
  1999年   281篇
  1998年   124篇
  1997年   125篇
  1996年   120篇
  1995年   101篇
  1994年   112篇
  1993年   95篇
  1992年   226篇
  1991年   230篇
  1990年   248篇
  1989年   203篇
  1988年   226篇
  1987年   227篇
  1986年   192篇
  1985年   213篇
  1984年   116篇
  1983年   107篇
  1982年   72篇
  1981年   72篇
  1980年   67篇
  1979年   86篇
  1978年   82篇
  1977年   62篇
  1971年   66篇
  1958年   69篇
  1957年   79篇
  1956年   76篇
  1955年   83篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
目的调查宁波市北仑区0~14岁儿童哮喘发病率、发病规律及危险因素,为制定防治措施提供参考。方法2013年1月-2014年1月,采用整群抽样法抽取北仑区19所学校0~14岁儿童为调查对象进行问卷调查,对筛查出的疑似哮喘儿童进行确诊,并对其人口学特征进行分析,采用logistic回归方程分析危险因素。结果调查收回有效问卷23 781份,共检出哮喘患儿534例,发病率为2.25%,男女发病率比例为1.92:1。其中发病较轻患儿占44.01%,中度占31.46%,重度占24.53%。发病时间以换季、冬季为主,分别占35.96%、32.02%。多因素logistic回归分析显示,呼吸道感染、药物过敏史、家族过敏史和食物过敏史是儿童哮喘发病的危险因素(P<0.05)。结论北仑区儿童哮喘发病率较高,具有性别和季节发病差异,应加大对患病危险因素的宣传,规范标准化治疗方案,减少儿童哮喘疾病的发生。  相似文献   
3.
Insomnia     
  相似文献   
4.
Reactive oxygen species and human spermatozoa: physiology and pathology   总被引:20,自引:1,他引:19  
The role of reactive oxygen species (ROS) in the pathophysiology of human sperm function has been emphasized in recent years. ROS production in semen has been associated with loss of sperm motility, decreased capacity for sperm–oocyte fusion and loss of fertility. There is a current presumption that the most prolific source of ROS in sperm suspensions is an NADPH oxidase located in leukocytes or in spermatozoa which produces superoxide which is further converted to peroxide by the action of superoxide dismutase. Hydrogen peroxide has been recognized as the most toxic oxidizing species for human spermatozoa, which are very sensitive to lipid peroxidation owing to the high content of polyunsaturated fatty acids in their plasma membrane, though this is not the sole mechanism by which sperm function might be impaired by ROS. Although the excessive production of ROS is detrimental to human spermatozoa, there is a growing body of evidence which suggests that ROS are also involved in the physiological control of some sperm functions. This review focuses on the nature and source of the ROS generated by human spermataozoa as well as their operational mechanisms and their effects, which may be detrimental or beneficial.  相似文献   
5.
6.
7.
Forty-five displaced olecranon fractures including 14 accompanying dislocated radial heads and seven radial head fractures were treated over a 13-year period by the tension band wiring technique. The use of supplemental internal fixation when necessary allows excellent results with the use of this technique, even in the presence of severe comminution or radial head dislocation. Primary silicone radial head implants fractured in all three patients in which they were used, necessitating repeat surgery in two patients to date. While loss of motion in terminal extension was a common aftermath of displaced olecranon fracture (59%), it was usually minor and functionally insignificant. True Kirschner-wire migration was not a common problem and can probably be eliminated by proper technique. The presence of gaps in the intraarticular surface of the semilunar notch of the ulna produced no ill effects and was compatible with excellent results. If only those cases with isolated olecranon fractures in this series are considered, there were good and excellent results in 29 of 30 cases (97%). Excision of the olecranon fragment(s) should be reserved for those cases when anatomic restoration cannot be achieved with internal fixation.  相似文献   
8.
If proven effective, vaginal microbicides and diaphragms will likely be part of a larger HIV prevention model that includes condoms and other prevention strategies. It is, therefore, important to understand how introducing new prevention methods may affect overall patterns of sexual risk behavior. Data presented were collected as part of a safety and feasibility study of ACIDFORM gel with a diaphragm among 120 women in South Africa. Interviews were administered at enrollment and months 1, 3, 5, and 6 of the trial. Focus groups were conducted at trial exit. Frequency of sex increased significantly after enrollment. This increase appears to be owing to perceived protection from HIV and greater sexual pleasure afforded by the gel. Male condom use was high overall but increased significantly from enrollment. Data suggest this is because of increased partner involvement, increased negotiating power afforded by study participation, and provision of free condoms perceived to be of high quality.  相似文献   
9.
10.
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