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   3012660篇
  免费   237662篇
  国内免费   6134篇
耳鼻咽喉   42975篇
儿科学   95854篇
妇产科学   81790篇
基础医学   427080篇
口腔科学   87040篇
临床医学   275597篇
内科学   583571篇
皮肤病学   63719篇
神经病学   249964篇
特种医学   119271篇
外国民族医学   1131篇
外科学   453552篇
综合类   72438篇
现状与发展   1篇
一般理论   1287篇
预防医学   244224篇
眼科学   71088篇
药学   223112篇
  7篇
中国医学   5726篇
肿瘤学   157029篇
  2018年   31139篇
  2016年   26753篇
  2015年   30091篇
  2014年   43036篇
  2013年   65863篇
  2012年   88104篇
  2011年   93093篇
  2010年   55207篇
  2009年   52583篇
  2008年   88077篇
  2007年   93709篇
  2006年   94739篇
  2005年   92030篇
  2004年   89023篇
  2003年   85814篇
  2002年   84103篇
  2001年   137846篇
  2000年   142645篇
  1999年   120397篇
  1998年   35044篇
  1997年   31785篇
  1996年   31412篇
  1995年   30451篇
  1994年   28594篇
  1993年   26558篇
  1992年   97328篇
  1991年   94354篇
  1990年   91429篇
  1989年   88147篇
  1988年   81439篇
  1987年   80592篇
  1986年   76168篇
  1985年   72992篇
  1984年   55348篇
  1983年   47217篇
  1982年   28810篇
  1981年   25682篇
  1980年   24057篇
  1979年   52020篇
  1978年   36759篇
  1977年   31081篇
  1976年   29307篇
  1975年   30778篇
  1974年   37922篇
  1973年   36088篇
  1972年   33673篇
  1971年   31269篇
  1970年   29222篇
  1969年   27236篇
  1968年   24885篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Computer competition analysis of 3H-DHA (3H-dihydroalprenolol, a nonselective beta-adrenergic radioligand) binding in the presence of unlabeled metoprolol (a beta 1-selective antagonist) indicates the existence of both beta 1- and beta 2-adrenergic receptor subtypes in the rat placenta and confirms previous reports that both beta-adrenoceptors are present in adult rat cortex. In the fetal brain (20th day of gestation), however, only beta 1-receptors were detected. Pregnant rats were chronically exposed to methadone from day 7 to day 20 of gestation via implanted osmotic minipumps (6.3-9.0 mg/kg/day). This treatment schedule did not induce a change in the affinity and density of either beta-receptor subtype in the placental, fetal and maternal brain homogenates. The results are discussed in terms of the reported monoaminergic and opiate receptor functional interactions.  相似文献   
992.
S R Roffler  M H Yu  B M Chen  E Tung  M Y Yeh 《Cancer research》1991,51(15):4001-4007
Pseudomonas exotoxin A (PE) linked to the F(ab')2 fragment of 1H10, a murine monoclonal antibody recognizing a carbohydrate epitope of a glycoconjugate expressed on the surface of human cervical carcinoma tumor cells, was evaluated for in vitro and in vivo activity. PE can kill cells by ADP-ribosylating elongation factor 2 thus inhibiting protein synthesis. Disulfide- as well as thioether-linked immunotoxins (1H10-PE) killed cervical carcinoma cells in vitro and were 20-160 times more inhibitory to target than to control cells. Cell killing was antibody mediated as demonstrated by the reduction of 1H10-PE growth inhibition to target CaSki cells by free 1H10 F(ab')2. In addition, a control antibody immunotoxin was nontoxic to CaSki cells. Thioether-linked 1H10-PE administered either i.v. or i.p. suppressed the growth of established solid s.c. cervical carcinoma tumors xenografted in nude mice for over 30 days. Treatment with antibody alone or a control immunotoxin had no significant effect on tumor growth. Administration of immunotoxin i.p. was associated with less toxicity than administration i.v., but i.v. injections were more effective at suppressing the growth of established solid tumors.  相似文献   
993.
994.
995.
Development of the genital and urinary systems is interwoven. Developmental abnormalities may cause problems in both systems, although the presenting problem may be ambiguous genitalia, hypospadias, undescended testis, or a urinary tract infection. The primary care physician must understand the underlying significance of pediatric urologic problems and seek appropriate consultation in a timely manner.  相似文献   
996.
Opsoclonus in organophosphate poisoning   总被引:1,自引:0,他引:1  
Transient opsoclonus was observed in a patient who attempted suicide with the organophosphate insecticide Malathion (diethyl[dimethoxyphosphinothioyl]thiobutanedioate). Several toxins can cause opsoclonus, and these must be considered in its differential diagnosis. Eye movement disorders are one of the more common manifestations of organophosphate intoxication, and opsoclonus should now be included among these. Acetylcholine may be a neurotransmitter in the ocular motor pathway.  相似文献   
997.
A patient with long-standing Tourette's syndrome had a dramatic exacerbation of symptoms following the rapid withdrawal of haloperidol. Clonidine administration resulted in a disappearance of tics, which recurred 6 days later. The role of clonidine in blocking withdrawal-induced symptoms in patients with Tourette's syndrome treated with long-term neuroleptics is discussed from a clinical and neurobiological perspective. The implications of this case for the treatment of supersensitivity psychosis and tricyclic withdrawal states with clonidine are also discussed.  相似文献   
998.
999.
1000.
Excessive glucose absorption and dialysate amino acid and protein losses contribute to malnutrition in children on glucose-based continuous ambulatory peritoneal dialysis (CAPD). We used 2.5 and 4.25% glucose and 1.1 and 2.0% amino acid dialysates to assess short-term effectiveness and nutritional consequences of amino acid-based dialysis solutions. Plasma and effluent urea and creatinine concentrations were similar with amino acid and glucose dialysis although 16% less fluid was removed with amino acid dialysates. Absorption of 77.3 +/- 5.3% of dialysate amino acids exceeded losses of amino acids and protein in glucose effluent. With amino acid dialysates, fasting plasma glucose concentrations were maintained while plasma amino acid levels rose, peaked at 1 h, and, excepting methionine, isoleucine, and phenylalanine with the 2.0% solution, returned to initial levels after 5 h. Compared with glucose, amino acid dialysates provide reduced but satisfactory fluid and waste removal, maintain normoglycemia, and more than compensate for effluent losses of amino acids and protein.  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