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   251180篇
  免费   12052篇
  国内免费   460篇
耳鼻咽喉   3251篇
儿科学   7854篇
妇产科学   5308篇
基础医学   35727篇
口腔科学   5656篇
临床医学   19843篇
内科学   55520篇
皮肤病学   6721篇
神经病学   22330篇
特种医学   7643篇
外国民族医学   101篇
外科学   31195篇
综合类   1231篇
一般理论   67篇
预防医学   23270篇
眼科学   4816篇
药学   17576篇
中国医学   759篇
肿瘤学   14824篇
  2023年   1330篇
  2022年   1165篇
  2021年   3997篇
  2020年   2355篇
  2019年   4413篇
  2018年   7885篇
  2017年   5147篇
  2016年   5169篇
  2015年   5757篇
  2014年   6314篇
  2013年   10002篇
  2012年   16961篇
  2011年   17044篇
  2010年   8662篇
  2009年   6622篇
  2008年   14690篇
  2007年   15706篇
  2006年   14485篇
  2005年   14359篇
  2004年   13501篇
  2003年   12375篇
  2002年   11709篇
  2001年   6551篇
  2000年   6735篇
  1999年   5982篇
  1998年   1103篇
  1997年   911篇
  1996年   835篇
  1995年   774篇
  1992年   3360篇
  1991年   2970篇
  1990年   2871篇
  1989年   2605篇
  1988年   2454篇
  1987年   2301篇
  1986年   2169篇
  1985年   1955篇
  1984年   1449篇
  1983年   1223篇
  1979年   1240篇
  1978年   880篇
  1977年   827篇
  1975年   826篇
  1974年   1010篇
  1973年   1018篇
  1972年   967篇
  1971年   946篇
  1970年   875篇
  1969年   932篇
  1968年   802篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
We tested the effects of pre-treatment with dexamethasone on topically induced ocular anaphylaxis in the rat. Rats were immunized with dinitrophenylated Ascaris suum extract and challenged with di-DNP-lysine. Dexamethasone was administered topically once (24, 6, or 1 h before challenge) or three times (6, 4, and 2 h before challenge). A single pre-treatment given at 24 or 6 h had no significant effect. A single pre-treatment 1 h before challenge reduced the extent of edema assessed histologically but not clinically, and had no significant effect on the eosinophil count in conjunctival tissue examined 6 h after challenge. Eyes pre-treated with dexamethasone 6, 4, and 2 h before challenge showed a significant reduction in conjunctival edema assessed histologically and clinically 1 h after challenge. In addition, 6 h after challenge the number of eosinophils was significantly reduced. We conclude that repeated pre-treatment with dexamethasone can suppress both the immediate phase and the cellular late phase of topically induced ocular anaphylaxis.  相似文献   
102.
Pyloromyotomy of Ramstedt: experience of a nonspecialized centre   总被引:2,自引:0,他引:2  
In a general hospital over a period of 6 years 57 infants with congenital hypertrophic stenosis underwent a Ramstedt pylorotomy. In most cases a surgical resident-in-training performed the operation under the direct supervision of a general surgeon. There were no complications of anesthesia, no deaths and no substantial morbidity. The majority of infants left the hospital within 48 hours. The results in this series compared favourably with those reported from more specialized centres.  相似文献   
103.
Osteopenia of the tibia and femur caused by an external fixator in the tibia was studied in 14 rabbits. Eight rabbits were treated with a complete unilateral external fixator in one tibia, whereas the other tibia served as control. The other 6 animals had one leg operated on with inserting of all the pins but without the frame. This technique was chosen to compare osteopenia caused by stress protection and the effect of the pins. After 6 weeks, we found a 7 percent reduction in the bone mineral content in the tibial diaphyseal segment between the pins of the external fixator and no bone loss in the tibia that were operated on with only pins. In the femurs, there was a smaller decrease in the bone mineral content: respectively 3.2 percent (complete frame) and 2.9 percent (only pins). On all the operated on tibiae, there was an increase in the bone mineral content around the pins both proximally and distally.  相似文献   
104.
The details of two consecutive groups of cleft palate patients treated with one- or two-stage palate repair are presented. The total number of patients is 237, with 128 operated in one stage, and 109 operated in two stages. In the two-stage group, the frequency of 'unintended' palatal fistulas decreased by 80%, and the use of blood transfusions was greatly reduced, but total operation time and hospital stay were longer. The results in terms of speech quality, facial growth and dental occlusion, will be reported on separately.  相似文献   
105.
The pharmacokinetics and pharmacodynamics of the anticholinergic and calcium antagonistic drug terodiline, N-tert-butyl-1-methyl-3,3-diphenylpropylamine, have been studied in beagle dogs. The bioavailability was about 25% (0.15 and 0.5 mg/kg), the terminal half-life 3 hr, the systemic clearance 40 ml/min..kg, the volume of distribution (V beta) about 7 l/kg and the unbound fraction in serum 0.14. p-Hydroxyterodiline and p-hydroxy-m-methoxyterodiline were quantitated and constituted 15-40% and 25%, respectively, of the amount excreted in urine (about 60% of the dose) and were the main metabolites, as in man. The dog was used as an experimental model to study the chronotropic effect. An increased heart rate was observed after acute administration of high doses of terodiline as well as after p-hydroxyterodiline. A 20% increase in heart rate was observed at a mean serum concentration of 1086 and 1010 micrograms/l following intravenous injection of terodiline or p-hydroxyterodiline, respectively. The corresponding unbound concentrations were 150 and 474 micrograms/l. The potency ratios of terodiline/p-hydroxyterodiline was 0.9 +/- 0.2 (based on total concentrations) and 3.2 +/- 0.8 (based on unbound concentrations). The estimated potency of parent drug and main metabolite and the fact that p-hydroxyterodiline constitutes 10-20% of the terodiline steady-state level in man, indicate that the contribution of the metabolite to the chronotropic effect observed in clinical studies is minor.  相似文献   
106.
We report the case of a 25-year-old man who had a penetrating keratoplasty for keratoconus. A year and a half after surgery a cyst was noted in the anterior chamber, which was observed to enlarge over six months. Because of anxiety about endothelial touch, it was removed surgically. Histologically the cyst was composed of stratified, non-keratinized squamous epithelium attached to loose fibrovascular tissue including islands of melanin-containing epithelial cells. This was interpreted as an epithelial implantation cyst of the anterior chamber of corneal origin attached to iris tissue.  相似文献   
107.
108.
Chronic thalamic-VIM stimulation was performed in 9 parkinsonian patients with disabling tremor and poor response to drugs. Neuropsychological assessment was performed before and after deep brain electrode implantation and stimulation. Mild cognitive disorders were observed prior to thalamic implantation. Neuropsychological testing failed to show intellectual function worsening after implantation and stimulation. We conclude that thalamic stimulation could be an appropriate treatment of untractable tremor as this could provide less neuropsychological side-effects than thalamotomy, especially in Parkinson's disease.  相似文献   
109.
The CD4+ CD8- inducer helper cell and the CD4- CD8+ cytotoxic/suppressor cell absolute numbers were measured in the peripheral blood of patients with various pathological conditions: with leukemia-lymphomas or solid tumors, patients with bone marrow grafts suffering from GvH, HIV-1 asymptomatic carriers, ARC and AIDS patients. The study was carried out during observation periods when they were not suffering from opportunistic infections and were untreated. In all the groups a decrease of the CD4+ CD8- cell absolute number was observed. In the leukemia-lymphoma and solid tumor bearing patients the CD4- CD8+ absolute value was lower than normal, while in the GvH- and HIV-infected patients, it was significantly higher. The clinical follow-up of each group indicates that GvH, ARC and AIDS patients developed infection in 40-68% of the cases, ie the only groups at risk of infection are those in which the CD4- CD8+ absolute values are high: we suggest that the balance CD4+ versus CD8+ should be considered rather the absolute CD4+ when discussing appropriate use of immuno-regulators.  相似文献   
110.
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