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   1082920篇
  免费   94800篇
  国内免费   4638篇
耳鼻咽喉   17779篇
儿科学   34885篇
妇产科学   28983篇
基础医学   135324篇
口腔科学   26774篇
临床医学   104500篇
内科学   236511篇
皮肤病学   26679篇
神经病学   89285篇
特种医学   43965篇
外国民族医学   336篇
外科学   187167篇
综合类   19868篇
现状与发展   72篇
一般理论   329篇
预防医学   74394篇
眼科学   23818篇
药学   67476篇
中国医学   1834篇
肿瘤学   62379篇
  2021年   9488篇
  2020年   9733篇
  2019年   9213篇
  2018年   16883篇
  2017年   14732篇
  2016年   16329篇
  2015年   17471篇
  2014年   28127篇
  2013年   35505篇
  2012年   33462篇
  2011年   35109篇
  2010年   27844篇
  2009年   30481篇
  2008年   34018篇
  2007年   34112篇
  2006年   36559篇
  2005年   33524篇
  2004年   31447篇
  2003年   29552篇
  2002年   29091篇
  2001年   45629篇
  2000年   46151篇
  1999年   39954篇
  1998年   13890篇
  1997年   12748篇
  1996年   12507篇
  1995年   11721篇
  1994年   10162篇
  1993年   9309篇
  1992年   30025篇
  1991年   28814篇
  1990年   27848篇
  1989年   26870篇
  1988年   24918篇
  1987年   24378篇
  1986年   23478篇
  1985年   22203篇
  1984年   16699篇
  1983年   14252篇
  1982年   8801篇
  1979年   15132篇
  1978年   10684篇
  1977年   9149篇
  1976年   8514篇
  1975年   9344篇
  1974年   11090篇
  1973年   10565篇
  1972年   10109篇
  1971年   9254篇
  1970年   8933篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Background : Methimazole, an anti-thyroid drug, was recently found to be useful in the treatment of systemic lupus erythematosus and other autoimmune diseases. Moreover, decreased thyroid hormone production is associated with a variety of immunological manifestations, such as reduced activation of CD4+ cells, increased CD8+ cell activity and reduced soluble IL-2 receptors. In the present study we examined the effects of methimazole and propylthiouracil on a rat model of experimental colitis.
Methods : Colitis was induced by intracolonic administration of 30 mg trinitrobenzene sulphonic acid (TNB). Two weeks prior to induction of colitis, rats were treated by either methimaziole (0.04%) or propylthiouracil (0.01%) in drinking water after a week of free access to water. Rats were sacrificed 48 h or 7 days after induction of colitis. The colon was isolated, rinsed with ice-cold water and weighed. Damage was assessed both macroscopically and microscopically and myeloperoxidase (MPO) activity determined.
Results : All treated rats were hypothyroid as manifested by a significant elevation of thyroid stimulating hormone (TSH), by comparison with the control groups (mean -1.82±0.40 versus 0.11±0.02 mmol/L, respectively). The inflammatory response elicited by TNB resulted in severe mucosal damage 48 h after damage induction, which persisted for 7 days. Pre-treatment with either methimazole 0.04% or propylthiouracil 0.01% significantly decreased mucosal damage macroscopically (lesion area, lesion score and segmental weight) microscopically and also significantly decreased MPO level at both time points ( P <0.01).
Conclusions : Methimazole and propylthiouracil significantly reduce mucosal damage and colonic weight in a rat model of colitis. The mode by which they do so remains to be studied.  相似文献   
102.
The efficacy and safety of ketoprofen and paracetamol were compared for the treatment of acute migraine in a randomized, double-blind study of 64 patients. Thirty-four patients received ketoprofen 100 mg intramuscularly, and 30 patients received paracetamol 500 mg intramuscularly. Partial or complete relief of pain and other symptoms was achieved 15 to 20 minutes after administration in the ketoprofen group and within 35 minutes in the paracetamol group. Complete relief of pain was achieved within 30 to 40 minutes after ketoprofen in 28 patients (82.5%) compared to 5 patients (17.5%) in the paracetamol group. Six of the patients treated with ketoprofen needed a second dose for complete relief of pain during the 4-hour follow-up period. Side effects were rare and minimal. Our findings suggest that ketoprofen produced statistically significant benefit in the treatment of acute migraine.  相似文献   
103.
104.
The results of the in vitro fertilisation programme at Tygerberg Hospital for the period April 1983 to January 1988 are presented. Of the 1117 laparoscopies performed, 825 patients reached the transfer stage. A live-birth rate of 9.3% was achieved. The pregnancy rate after transfer of 4 embryos was 25.9% compared with 15.4% after 2 embryos and 10.8% after 3 embryos (P = less than 0.0001). The multiple pregnancy rate was 2.8% in the group receiving 2 embryos and 11.7% and 10.4% in those receiving 3 and 4 embryos, respectively. Of the 77 successful pregnancies (90 babies), 1 baby died at 34 weeks' gestation as the result of abruptio placentae due to preeclampsia and 1 cot death occurred. The only congenital abnormality encountered was a cleft palate.  相似文献   
105.
Nine hundred and three patients undergoing diagnostic peritoneal lavage (DPL) over a 6-year period were retrospectively reviewed to evaluate the utility of the white blood cell (WBC) count in the lavage fluid. Eleven patients (1.2%) had dialysate WBC counts greater than 500/mm3, with erythrocyte counts less than 10(5)/mm3. Nine of these patients who were lavaged within 4 hours of injury had no intra-abdominal pathology. Two patients, lavaged after 4 hours, demonstrated intra-abdominal injury. Two hundred twenty-three patients (24.7%) had grossly clear dialysate which was not sent for laboratory analysis. None of these patients required laparotomy. We conclude that the WBC count in DPL fluid is of no diagnostic value in victims of blunt abdominal trauma who are lavaged within 4 hours of injury. In addition, laboratory analysis of clear dialysate is not required in these patients.  相似文献   
106.
Patients on long-term haemodialysis suffer from dialysis arthropathy due to the deposition of dialysis amyloid. We investigated the use of 99Tc-labelled methylene diphosphonate bone scans in 17 patients as a possible in vivo diagnostic technique. In most clinically affected joints, with the exception of shoulders and hands, there was increased radioisotope uptake consistent with uptake by periarticular bone. In addition, we describe intense soft-tissue uptake around some clinically affected large joints. In contrast, control groups of patients on haemodialysis without arthropathy and patients without renal failure did not have increased uptake. A semi-quantitative scale of uptake was devised, and the following correlations were significant: pain perception and isotope uptake score in the ankles and feet, and the number of radiological lesions and isotope uptake scores in the wrists and knees. The following sites where the radioisotope might bind in the affected joints are proposed: amyloid deposits, areas of soft-tissue calcification, or areas of increased bone turnover. It is concluded that whereas the scanning technique cannot make a definite diagnosis of amyloid and, therefore, cannot be expected to supersede histological diagnosis, it is a useful adjuvant investigation, of particular importance in those patients unable or unwilling to undergo biopsy.  相似文献   
107.
108.
Cyanoacrylate-based glues have been reported as producing dermatitis and bronchial asthma. The paper describes the case of a patient occupationally exposed to Loctite 406, who developed irritation of the skin and mucosae of the face and late bronchial asthma. Preventive measures for subjects exposed to cyanoacrylic instant glues are discussed.  相似文献   
109.
Patient history and clinical examination are important for the diagnosis of degenerative joint disease. Here the typical statements of a patient suffering from early osteoarthritis are described and, as far as possible, explained. The joint in question must be systematically examined. Furthermore, the neighboring joints and soft-tissue structures, i.e., muscles, tendons etc., should be examined and evaluated with respect to their importance in hindering the functional chain. The neuroreflectory mechanisms involved herein are described.  相似文献   
110.
BACKGROUND: The aim was to determine the influence of the socioeconomic status of the family and the hygienic practices in the home on the prevalence of head lice infestation in children. METHODS: The study was carried out by analyzing the answers to a standardized epidemiological questionnaire given to parents of school children aged 4-17 in Bet Shemesh, a medium-sized urban town 25 km from Jerusalem. RESULTS: Of 3,000 questionnaires distributed, 958 (31.9%) were completed and returned. The majority of the children (72.4%) had been previously infested with lice. Half of them had other family members, mainly brothers and sisters, who had been infested in the past with lice. In 97.5% of the families the mother was responsible for examining the children for lice, and for carrying out treatment when infestation was present. An association was found between presence of lice infestation and mother's education, age of child, and frequency of shampooing, combing, and examination for lice. There was no association between infestation rates and mother's country of origin, crowding in the home, and the sharing of combs, brushes, hats, scarves, towels, and clothes. CONCLUSIONS: There is evidence that the incidence of lice infestation depends on the hygienic practices in the home rather than on the socioeconomic status of the family or sharing of personal articles among family members.  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