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   99053篇
  免费   4028篇
  国内免费   218篇
耳鼻咽喉   1458篇
儿科学   3114篇
妇产科学   2502篇
基础医学   13438篇
口腔科学   2642篇
临床医学   6010篇
内科学   22794篇
皮肤病学   2782篇
神经病学   7697篇
特种医学   2230篇
外国民族医学   2篇
外科学   12441篇
综合类   543篇
一般理论   25篇
预防医学   11187篇
眼科学   2249篇
药学   7406篇
  1篇
中国医学   314篇
肿瘤学   4464篇
  2023年   552篇
  2022年   328篇
  2021年   1623篇
  2020年   824篇
  2019年   1892篇
  2018年   3329篇
  2017年   1976篇
  2016年   1889篇
  2015年   2185篇
  2014年   2312篇
  2013年   3767篇
  2012年   6379篇
  2011年   6456篇
  2010年   3304篇
  2009年   2379篇
  2008年   5314篇
  2007年   5639篇
  2006年   5489篇
  2005年   5528篇
  2004年   5072篇
  2003年   4735篇
  2002年   4494篇
  2001年   3190篇
  2000年   3407篇
  1999年   2693篇
  1998年   496篇
  1997年   327篇
  1996年   369篇
  1992年   1301篇
  1991年   1176篇
  1990年   1111篇
  1989年   981篇
  1988年   906篇
  1987年   904篇
  1986年   832篇
  1985年   807篇
  1984年   600篇
  1983年   477篇
  1979年   598篇
  1978年   356篇
  1976年   340篇
  1975年   362篇
  1974年   531篇
  1973年   493篇
  1972年   434篇
  1971年   390篇
  1970年   473篇
  1969年   435篇
  1968年   418篇
  1967年   376篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
A technique to anesthetize turtles with ether is presented, in which a plastic cannula is passed through the glottis into the trachea. This procedure avoids apnea and allows ether vapours obtained from a chamber to be introduced, by the animal respiratory movements or by means of a pump, into the animal lungs. The anesthesia is rapidly obtained and lasts from 45-90 minutes. The time of recovery from anesthesia ranged from 60-90 minutes. With this technique no deaths were observed and the same animal could be anesthetized repeatedly.  相似文献   
62.
63.
64.
We have analyzed the cellular and humoral immunity to the mycobacterial 65 KDa heat shock protein (hsp65) in a group of Freund's Adjuvant-immunized rats with a limited susceptibility to Adjuvant arthritis. According to the arthritis indices during the period of study (35 days), two different groups of rats could be distinguished; a) autoimmune Adjuvant arthritic rats (AA), and b) Non-arthritic animals (NA), including both rats which did not display any disease symptoms and rats suffering mild transient inflammation. The cellular response to the immunizing agent (Mycobacterium tuberculosis) or the mitogen Concanavalin A was comparable between both groups of rats. However, we detected an impaired cellular response to the individual hsp65 antigen in the animals that did not develop the disease. On the contrary, the level of hsp65-specific antibodies was much higher in NA animals than in AA rats suggesting a protective role for the hsp65 specific antibodies.  相似文献   
65.
A 76-year-old woman with an inferior wall myocardial infarction, with right ventricular involvement, developed severe arterial hypoxemia with neurological involvement. Pulmonary edema or embolism and chronic obstructive pulmonary disease were ruled-out, and a right-to-left shunt was demonstrated by contrast echocardiography at the level of the foramen ovale. After inotropic support and oxygen supplementation, the patient recovered, although with significant neurological sequelae. No focal lesions were detected in the central nervous system by computerized tomography. Hypoxemia improved, coinciding with the disappearance of right-to-left shunt by contrast echocardiography.  相似文献   
66.
Captopril is a suitable drug to treat high blood pressure in diabetic patients. This Angiotensin-Converting Enzyme Inhibitor (ACEI) is a vasodilator without tachycardia and saline retention. Furthermore, captopril is one of antihypertensive drugs with less adverse effects. It does not induce metabolic changes, improves glucose tolerance and brake the evolution of renal insufficiency. About 50-60% of patients are under control (DBP < 90 mmHg) with captopril monotherapy. In the present paper, were included 64 women and 16 men with diabetes mellitus and mild-moderate hypertension, I-II phase WHO. The average age (mean +/- S.D.) was 66.6 +/- 9.2 years. All patients were treated with 25 mg/12 h of captopril, for one month. If blood pressure was not under control, captopril treatment enhanced to 50 mg/12 h during second month. After this period of two months, patients under control were got out of this study. 37 patients (46.25%) needed a second drug. In randomized form, 20 patients associated 25 mg HCTZ one time a day (CAP + HCTZ); and 17 patients associated 20 mg/12 h of nifedipine retard (CAP + NIF). The study continued for 4 months more. Both treatments reduced blood pressure in significant form without changes statistical significant in the heart rate, weight, glycemia, cholesterol, triglycerides, c-HDL, uric acid, creatinine, Na+ and K+ blood levels. CAP + HCTZ controlled (DBP < 90 mHg) 85% and CAP + NIF 81.25% of patients.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
67.
We compared three different microsurgical vasovasostomy techniques on the rat vas deferens using absorbable and non-absorbable sutures and a fibrin adhesive technique. The best method was an extramucosal technique over a splint using vicryl. The worst results were seen using adhesive.  相似文献   
68.
The aim of the study was the investigation of the biochemical condition of elements likely to directly participate in active closing of the urethral lumen. We estimated glycogenolysis in urinary bladder, perivesical connective tissue and levator ani muscle (LAM) samples obtained intraoperatively from 80 stress incontinent women. Glycogen content as well as activities of active and total glycogen phosphorylase and acid exo-1,4-alpha-glucosidase were measured. Material from the urinary bladder and perivesical connective tissue was insignificantly altered, and glycogen contents in the bladder (2.03±1.38 g/100 g wet tissue) were considered to be normal. In the LAM glycogenolysis was much more activated than in other tissues (p<0.001 by Fischer's exact test). Of LAM specimens 78% (22/28) revealed imbalanced biochemistry of glycogen with activation of hydrolytic decomposition. We conclude that stress urinary incontinence in women is frequently associated with metabolic alterations in the periurethral striated fibres. This study indirectly supports our recent hypothesis on the pathogenesis of the disease in terms of muscle fibre type transitions.  相似文献   
69.
A retrospective cohort study of mortality and cancer morbidity was carried out among 295 marine engineers and 182 machinists with special regard to cancer of the lung. The cohort was defined as all graduates from engineering and machinists school in Iceland during 1936-1955. During vocational training, as well as in their professional lives, marine engineers and machinists are exposed to asbestos, different kinds of mineral oils, and exhaust gases with marked individual variation as regards mode and magnitude of exposure. For deaths occurring between 1951 and 1982 information was obtained from the Statistical Bureau of Iceland. Significantly increased standardized mortality ratios were determined for cancer of the trachea, bronchus, and lung for the entire cohort. Record linkage with the Cancer Register revealed 36 cancers in the period 1955-1982. No statistically significant excess was found for the overall cancer incidence or for the incidence of cancer at any particular site. A special survey of smoking status showed that cigarette smoking was not as common among the subjects of the cohort as among the general male population in Reykjavik. These results support the suggestion that the increased mortality of lung cancer in the study group had a causal relationship to occupational exposure, particularly to asbestos exposure.  相似文献   
70.
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