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   484224篇
  免费   30138篇
  国内免费   3610篇
耳鼻咽喉   6594篇
儿科学   11012篇
妇产科学   13872篇
基础医学   69316篇
口腔科学   14971篇
临床医学   38439篇
内科学   97392篇
皮肤病学   10665篇
神经病学   34424篇
特种医学   17488篇
外国民族医学   87篇
外科学   75448篇
综合类   13430篇
现状与发展   1篇
一般理论   98篇
预防医学   25573篇
眼科学   11969篇
药学   39876篇
  1篇
中国医学   2761篇
肿瘤学   34555篇
  2021年   3519篇
  2019年   3619篇
  2018年   5859篇
  2017年   4364篇
  2016年   4472篇
  2015年   5195篇
  2014年   7251篇
  2013年   9467篇
  2012年   13100篇
  2011年   13562篇
  2010年   8164篇
  2009年   7601篇
  2008年   12442篇
  2007年   13520篇
  2006年   13412篇
  2005年   12151篇
  2004年   11580篇
  2003年   11096篇
  2002年   10638篇
  2001年   33708篇
  2000年   34487篇
  1999年   28356篇
  1998年   6615篇
  1997年   5369篇
  1996年   4639篇
  1995年   4237篇
  1994年   3811篇
  1993年   3533篇
  1992年   19211篇
  1991年   18067篇
  1990年   17238篇
  1989年   16984篇
  1988年   15476篇
  1987年   14805篇
  1986年   13739篇
  1985年   12866篇
  1984年   8718篇
  1983年   7170篇
  1982年   3581篇
  1979年   7285篇
  1978年   4497篇
  1977年   3922篇
  1975年   3804篇
  1974年   4396篇
  1973年   4242篇
  1972年   4136篇
  1971年   3984篇
  1970年   3623篇
  1969年   3647篇
  1968年   3249篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
In rodents, chronic estrogenization has been shown to induce degeneration of dendrites and myelin figures in the hypothalamic arcuate nucleus adjacent to peroxidase-positive astrocyte processes. Because in this brain region estradiol is metabolized to 2-hydroxyestradiol (catecholestrogen), we hypothesized that the latter may be oxidized by the astrocytic peroxidase activity to cytotoxic ortho-semiquinones as occurs in peripheral tissues. Cysteamine induces nonenzymatic peroxidase activity in cultured astroglia identical to that observed in vivo. Using electron spin resonance, we demonstrate robust peroxidase-catalyzed oxidation of 2-hydroxyestradiol and dopamine by cysteamine-pretreated astrocyte cultures relative to untreated controls. These results implicate the peroxidase-positive astrocytes in the pathogenesis of estradiol-related hypothalamic damage, parkinsonism, and other free-radical-related neurologic disorders.  相似文献   
82.
A new macrolide antibiotic, clarithromycin (TE-031, A-56268), was studied for its clinical efficacy in the field of pediatrics. Patients treated were infants and children ranging from 2 months to 11 years old suffering from acute bronchitis in 5 cases, acute tonsillitis in 2 cases, Mycoplasma pneumonia in 2 cases, pertussis in 6 cases, scarlatina in 1 case and acute enteritis in 2 cases, a total of 18 cases. TE-031 was administered 19.7-43.5 mg/kg in daily doses and lengths of treatment ranged from 4 to 19 days. As regards to its clinical efficacy, good or excellent results were obtained in all cases: excellent in 11 cases and good in 7 cases. No clinical side effects nor abnormal laboratory test values obviously attributable to TE-031 were observed.  相似文献   
83.
Following administration of phenothiazines for schizophrenia, a 25-year-old patient developed a malignant neuroleptic syndrome followed by bilateral periarticular ossification of the knees, with severely limited motion. Two years later, the patient regained useful motion after bilateral excision of the ossified tissue and intensive physiotherapy. No recurrence of ossification was observed 3 years after operation, and the patient has maintained almost normal motion.  相似文献   
84.
85.
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   
86.
87.
88.
89.
90.
Q Guo  Z Guo 《中西医结合杂志》1989,9(8):472-4, 452
The effect of the traditional Chinese medicinal herbs enema and enteric-coated capsules in the treatment of ulcerative colitis (UC) were compared in 260 cases. The immune complexes and the dynamic change of autoantibodies were monitored in 28 out of the 260 cases before and after treatment. The following results were observed. (1) There was no significant difference in the total effective rate between the enema group and the oral capsule group (93.3% and 87.5% respectively), but the recovery rates of purulent hemafecia, mucusfecia and erosion accompanying colitis, etc. in the former group were higher than those in the latter (P less than 0.01). (2) The circulating immune complexes were found 43 times above the normal range in 17 cases with positive rate 60.7%, and tended to decrease as the condition became better after treatment. Antinuclear antibodies were determined by the indirect fluorescent immune method and the indirect enzyme labelling method and the positive rates were 53.6% and 64.7% respectively, both being much higher than those in the controls (P less than 0.01).  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