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   58641篇
  免费   3756篇
  国内免费   502篇
耳鼻咽喉   991篇
儿科学   896篇
妇产科学   1050篇
基础医学   9294篇
口腔科学   1775篇
临床医学   5687篇
内科学   11351篇
皮肤病学   2015篇
神经病学   4725篇
特种医学   3121篇
外科学   6925篇
综合类   288篇
现状与发展   3篇
一般理论   24篇
预防医学   3259篇
眼科学   1051篇
药学   5325篇
中国医学   722篇
肿瘤学   4397篇
  2024年   48篇
  2023年   504篇
  2022年   1320篇
  2021年   2133篇
  2020年   1135篇
  2019年   1662篇
  2018年   2057篇
  2017年   1620篇
  2016年   2175篇
  2015年   2903篇
  2014年   3127篇
  2013年   3814篇
  2012年   5602篇
  2011年   5320篇
  2010年   3034篇
  2009年   2399篇
  2008年   3612篇
  2007年   3340篇
  2006年   2991篇
  2005年   2784篇
  2004年   2315篇
  2003年   2058篇
  2002年   1789篇
  2001年   614篇
  2000年   553篇
  1999年   471篇
  1998年   274篇
  1997年   230篇
  1996年   197篇
  1995年   142篇
  1994年   132篇
  1993年   120篇
  1992年   176篇
  1991年   190篇
  1990年   166篇
  1989年   141篇
  1988年   129篇
  1987年   121篇
  1986年   130篇
  1985年   99篇
  1984年   105篇
  1983年   69篇
  1982年   67篇
  1981年   73篇
  1980年   55篇
  1979年   77篇
  1978年   54篇
  1975年   67篇
  1972年   52篇
  1971年   60篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Acute abdomen     
Acute surgical abdomen is the object of urgent surgical attention. The objective of emergency operation is to interrupt a process that has a steadily worsening prognosis on a scale of hours unless effective surgical treatment is rendered. There are basically three processes to address: free or incipient sepsis and peritonitis, gastrointestinal soilage, and hemorrhage.  相似文献   
62.
A double blind placebo controlled study was carried out in 40 subjects newly referred for treatment for obesity to determine the effects of the new thermogenic beta adrenoceptor agonist BRL 26830A. The subjects were randomised to receive either BRL 26830A, 200 mg daily for two weeks then 400 mg daily, or placebo for 18 weeks, and all were instructed to follow a 3.35 MJ diet that was low in fat and high in fibre. Weight loss was 15.4 (SD 6.6) kg in subjects given BRL 26830A compared with 10.0 (5.9) kg in those given placebo (p = 0.02). The relative weight loss was 0.93 (0.39%) a week with BRL 26830A and 0.61 (0.38)% with placebo (p = 0.02). Urinary excretion of nitrogen was similar in both groups, whereas measurements of skinfold thickness indicated a 4.1 kg difference in the amount of fat lost, suggesting that weight loss with BRL 26830A was mainly from adipose and not lean tissue. BRL 26830A had no effect on resting pulse rate or pressor effects on either diastolic or systolic blood pressure. No significant differences were found between the two groups in serum cholesterol concentration, percentage of high density lipoprotein cholesterol, plasma concentrations of glucose and insulin, the ratio of glucose to insulin, serum concentrations of triiodothyronine and thyroxine, and creatinine clearance. Short term administration of BRL 26830A to six subjects who had taken the drug for 18 weeks showed that the expenditure of energy increased by 11.6% during the second hour after administration, which suggests that BRL 26830A may enhance weight loss thermogenically. BRL 26830A may be a useful drug in the treatment of obesity.  相似文献   
63.
64.
This study was conducted to determine whether alcoholic and control subjects respond differently to manipulations that either enhance personal involvement (PI) or reduce negative affect (R, relaxation) on tests of neuropsychological function. In Phase 1, 48 male alcoholics and 36 male control subjects completed neuropsychological tasks under standard instructional sets. In Phase 2, subjects completed equivalent forms of these tests under one of three randomly assigned conditions; the PI condition in which subjects were encouraged to identify specific ways of improving their performance, the R condition in which subjects participated in a short relaxation exercise designed to reduce anxiety, or a No Treatment (NT) condition in which no attempt to manipulate the subjects' involvement or affect was made. Alcoholics were inferior to controls in both Phase 1 and Phase 2 [Fs (1,82) > 5.03, ps < 0.03]. The experimental manipulation differentially affected measures of negative affect and effort in the predicted direction. There were no group x condition interactions. Alcoholic and control subjects responded comparably to the experimental manipulations. This investigation, in combination with others using related manipulations, reinforces the hypothesis that alcohol-related cognitives dysfunction reflects an underlying deficit in brain states.  相似文献   
65.
OBJECTIVE: Patients on L-thyroxine with a 'suppressed' TSH (< 0.05 mU/l) were compared to those in whom TSH was detectable but not elevated (0.05-4.0 mU/l), with regard to morbidity data. DESIGN: Biochemical data from Tayside Thyroid Register was matched to hospital admissions data obtained from Health Board Statistics. PATIENTS: The patients were identified from those registered on the computerized Tayside Register. MEASUREMENTS: Serum T4 and TSH assays, clinical assessment scores, and admission records with regard to ischaemic heart disease, overall fractures, fractured neck of femur and breast carcinoma. RESULTS: Over one year, 1180 patients on thyroxine replacement had clinical and biochemical assessment; 59% had a suppressed TSH and 38% 'normal' TSH. Patients with a suppressed TSH exhibited higher median serum thyroxine levels (146 nmol/l, range 77-252 vs 119 nmol/l, 58-224; P < 0.001). Patients under the age of 65 years on L-thyroxine had an increased risk of ischaemic heart disease compared to the general population (female 2.7 vs 0.7%, P < 0.001; male 6.4 vs 1.7%, P < 0.01), but the risk was no different between those with suppressed and normal TSH. There was no increase in risk for overall fracture, fractured neck of femur or breast carcinoma in those on thyroxine with suppressed or normal TSH. CONCLUSION: Patients under the age of 65 years on L-thyroxine had an increased risk of ischaemic heart disease. There was no excess of fractures in patients on L-thyroxine even if the TSH is suppressed.  相似文献   
66.
67.
68.
Although adenocarcinoma is a well known complication of chronic inflammatory bowel disease, primary gastrointestinal lymphoma occurring in Crohn's disease is rare. A 40-year-old man with 10 year-history of Crohn's disease had multiple longitudinal ulcerative lesions on descending colon in follow-up colonoscopic examination. Microscopic examination of proximal descending colon revealed peripheral T cell lymphoma and other site of the descending colon was consistent with Crohn's disease. The patient reached complete remission of malignant lymphoma after three cycles of combined chemotherapy. He has been well for 10 months with sulfasalazine maintenance therapy but was admitted to the hospital due to spontaneous bowel perforation of ascending colon. Right hemicolectomy was done, but the patient died of post-surgical recurrent mesenteric abscess and sepsis. To the best of our knowledge, this is the first case of Non-Hodgkin's lymphoma complicating Crohn's disease in Korea which was confirmed by immunohistochemical studies.  相似文献   
69.
BACKGROUND & AIMS: Refractory celiac disease (RCD) may be subdivided into RCD types I and II with phenotypically normal and aberrant intraepithelial T-cell populations, respectively. In RCD II, transition into enteropathy-associated T-cell lymphoma (EATL) is seen frequently. We have evaluated the effect of cladribine (2-CDA), a purine analogue inducing T-cell depletion, on clinical, histopathologic, and immunologic parameters, as well as the toxicity and side effects in a group of RCD II patients. METHODS: Between 2000 and 2005, 17 patients were included (8 men, 9 women). All patients had a clonal rearrangement of the T-cell receptor gamma gene and immunophenotyping showed an aberrant T-cell population lacking surface expression of CD3, CD8, and T-cell receptor alphabeta, in the presence of expression of surface CD103 and intracytoplasmic CD3. Treatment consisted of 2-CDA (0.1 mg/kg/day) intravenously for 5 days, given in 1-3 courses every 6 months depending on the response. RESULTS: All patients tolerated 2-CDA without serious side effects. Six patients (35.8%) showed a clinical improvement (weight gain, improvement of diarrhea, and hypoalbuminemia). In 10 patients (58.8%) a significant histologic improvement and in 6 patients (35.2%) a significant decrease in aberrant T cells was seen. Seven patients (41.1%) developed EATL and died subsequently. One patient died of progressive refractory state with emaciation. CONCLUSIONS: Treatment with 2-CDA in RCD II is feasible, well tolerated, and can induce clinical and histologic improvement as well as a significant decrease of aberrant T cells in a subgroup of patients, albeit it does not prevent EATL development. However, the earlier reported potential risk of precipitating an overt lymphoma should be taken into consideration.  相似文献   
70.
In contrast to other types of congenital heart defects, the treatment of hypoplastic left heart syndrome (HLHS) has become comparably successful only within the last decade. Postnatal management of circulatory disturbances of HLHS was previously often performed, similarly to other types of neonatal shock, without considering the peculiarities of postnatal hemodynamics. It is of overwhelming importance to limit pulmonary hyperperfusion by reducing systemic afterload and avoiding artificial respiration. The invention of selective hypothermic cerebral perfusion using the modified Blalock-Taussig shunt has decreased the need for long circulatory arrest times involving the brain, and promises a better neurological outcome. Postoperatively, sophisticated hemodynamic monitoring is mandatory to provide sufficient systemic oxygen delivery. α-blockers are usually given for strong afterload reduction. Hospital mortality is as low as 10–15% in centers experienced with the Norwood operation. The next surgical steps to create a serial systemic and pulmonary circulation involve superior cavopulmonary anastomosis performed as early as possible (4–6 months) and finally total cavopulmonary connection at an age of 3–4 years.  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