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   537464篇
  免费   28123篇
  国内免费   579篇
耳鼻咽喉   6804篇
儿科学   17004篇
妇产科学   12689篇
基础医学   93975篇
口腔科学   12455篇
临床医学   49179篇
内科学   96723篇
皮肤病学   12078篇
神经病学   34473篇
特种医学   20091篇
外国民族医学   53篇
外科学   79018篇
综合类   7637篇
现状与发展   2篇
一般理论   109篇
预防医学   38864篇
眼科学   12085篇
药学   42064篇
  1篇
中国医学   1259篇
肿瘤学   29603篇
  2021年   4188篇
  2019年   4096篇
  2018年   5992篇
  2017年   4341篇
  2016年   5165篇
  2015年   5783篇
  2014年   7561篇
  2013年   11002篇
  2012年   16294篇
  2011年   18109篇
  2010年   10391篇
  2009年   9162篇
  2008年   16232篇
  2007年   17884篇
  2006年   17312篇
  2005年   16617篇
  2004年   16161篇
  2003年   15471篇
  2002年   14960篇
  2001年   22516篇
  2000年   23055篇
  1999年   18976篇
  1998年   5258篇
  1997年   4389篇
  1996年   4421篇
  1995年   4137篇
  1992年   14424篇
  1991年   15828篇
  1990年   15965篇
  1989年   15637篇
  1988年   14322篇
  1987年   14207篇
  1986年   13174篇
  1985年   12698篇
  1984年   9398篇
  1983年   8004篇
  1982年   4180篇
  1979年   8939篇
  1978年   6382篇
  1977年   5150篇
  1976年   5506篇
  1975年   6618篇
  1974年   7423篇
  1973年   7161篇
  1972年   6598篇
  1971年   6313篇
  1970年   5888篇
  1969年   5469篇
  1968年   5164篇
  1967年   4623篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
121.
The oncocytic Schneiderian papilloma (OSP) is a rare neoplasm of the nose and paranasal sinuses. The majority of the approximately twenty patients reported in the literature with this papilloma have been over the age of fifty at the time of diagnosis. The 33-year-old woman reported here is the youngest patient with this lesion to date. The OSP should be considered in the work-up of all unilateral nasal polypoid lesions. This lesion's propensity for recurrence and its documented association with synchronous malignant disease warrant surgical excision by en bloc resection of the lateral nasal wall, with corresponding careful microscopic evaluation of all excised tissue.  相似文献   
122.
In a double-blind study, mice were injected intraperitoneally with 0.2 ml 0.2% octoxynol-9 (O-9), 0.2 ml 0.2% nonoxynol-9 (N-9), or 0.2 ml saline (control) daily for 24 days. Another control group received no treatment. All mice were immunized twice with sheep red blood cells (SRBC) and bled by caudal incision. Mice receiving N-9 lost weight (P less than 0.02), had smaller livers (P less than 0.05), and showed enlarged spleens (P less than 0.05). The N-9-treated mice did not differ from either control group in the primary or secondary anti-SRBC responses, leukocyte (WBC) counts, or in the sizes of the kidneys, hearts, lungs, or thymuses. Mice receiving O-9 showed no significant differences from either control group in any of these tests. Serum immunoglobulin M (IgM) and immunoglobulin G (IgG) levels were similar in mice treated with O-9, N-9, or saline. All 3 groups had higher levels of both classes of immunoglobulins on day 16 than did untreated controls. This study shows that O-9, given to mice in doses 3 times that used by humans, is nontoxic, whereas the same dose of N-9 has minor deleterious effects.  相似文献   
123.
124.
125.
Using cortical cups in chloralose-urethanized rats, the in vivo release of cholecystokinin-like immunoreactivity (CCK-LI) from cerebral cortex was examined. Resting levels of cholecystokinin-like immunoreactivity ranged from 20 to 30 pg/20 min sample. The addition of potassium (40 mM) in excess, resulted in a highly significant elevation in the levels of CCK-LI in the cortical superfusate. Deletion of calcium and the substitution of cobalt (10 mM), resulted in a significant reduction in both resting release and the release otherwise evoked by the addition of potassium. Focal electrical stimulation of the cortex (20 Hz), resulted in a significant (1.9 +/- 0.2-fold, n = 8) increase in the levels of CCK-LI. The addition of glutamate (10(-6)-10(-4) M) of kainic acid (10(-8)-10(-6) M), also resulted in significant elevations in the levels of CCK-LI. The co-administration of a putative glutamate receptor antagonist, kynurenic acid (10(-4) M) resulted in a significant reduction in the levels of release otherwise evoked by the addition of glutamate, but not by electrical stimulation. The addition of GABA (10(-5)-10(-3) M) resulted in a dose-dependent decrease in the resting release of CCK-LI, and the release evoked by glutamate. Picrotoxin (10(-6)-10(-4) M), resulted in a highly significant increase in the levels of CCK-LI in the cortical effluent. These results are consistent with a tonic GABAergic inhibition of CCK-releasing neurons. The treatment of the animal with diazepam (30 mg/kg, i.p.) also resulted in a significant reduction in resting release and the release otherwise evoked by focal cortical stimulation.  相似文献   
126.
Inborn errors of the urea cycle are an important cause of hyperammonaemia throughout childhood, and are associated with high morbidity and mortality rates. If they are diagnosed early and treated appropriately, the outcome for affected children is significantly improved.  相似文献   
127.
128.
Biliopancreatic diversion is a very effective method for weight reduction. In some instances it is too effective and needs to be revised.  相似文献   
129.
130.
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