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   159062篇
  免费   4728篇
  国内免费   450篇
耳鼻咽喉   2603篇
儿科学   4724篇
妇产科学   3542篇
基础医学   21091篇
口腔科学   5661篇
临床医学   9997篇
内科学   38163篇
皮肤病学   5025篇
神经病学   12634篇
特种医学   3957篇
外国民族医学   2篇
外科学   18840篇
综合类   989篇
一般理论   43篇
预防医学   15236篇
眼科学   3405篇
药学   10958篇
  8篇
中国医学   879篇
肿瘤学   6483篇
  2024年   812篇
  2023年   1063篇
  2022年   1719篇
  2021年   4215篇
  2020年   2128篇
  2019年   4004篇
  2018年   5660篇
  2017年   3349篇
  2016年   3207篇
  2015年   3603篇
  2014年   4805篇
  2013年   6920篇
  2012年   10814篇
  2011年   11648篇
  2010年   6168篇
  2009年   4779篇
  2008年   8978篇
  2007年   9492篇
  2006年   8790篇
  2005年   8747篇
  2004年   7821篇
  2003年   7269篇
  2002年   6747篇
  2001年   4391篇
  2000年   4977篇
  1999年   3894篇
  1998年   957篇
  1997年   753篇
  1996年   654篇
  1995年   554篇
  1994年   445篇
  1993年   383篇
  1992年   1511篇
  1991年   1259篇
  1990年   1138篇
  1989年   979篇
  1988年   843篇
  1987年   784篇
  1986年   788篇
  1985年   685篇
  1984年   478篇
  1983年   414篇
  1979年   440篇
  1975年   322篇
  1974年   382篇
  1973年   387篇
  1972年   329篇
  1971年   359篇
  1970年   323篇
  1969年   346篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
51.
We investigated the expression of intercellular adhesion molecule-1 (ICAM-1) and lymphocyte function-associated antigen-3 (LFA-3) by thyrocytes and their regulation by cytokines. Immunofluorescence studies on cryostat sections and on freshly dispersed cell preparations showed that ICAM-1 and LFA-3 are barely detectable in non-autoimmune thyrocytes. However, thyrocytes acquired ICAM-1 expression in culture. IFN-gamma, IL-1 beta and TNF-alpha produced a clear enhancement of ICAM-1 expression. When tested in combination, IL-1 beta and TNF-alpha were additive to the IFN-gamma effect. LFA-3 expression was not modulated by these cytokines. In the HT93 thyroid cell line generated by transfection with SV40, ICAM-1 and LFA-3 were both constitutively expressed at high levels. Cytokines modulated ICAM-1 expression similarly, but to a greater extent than in normal thyrocytes. LFA-3 remained unmodified. These results support the notion that normal thyrocytes are immunologically silent cells. The capability of cytokines to induce ICAM-1 together with HLA class I and class II-expression on thyrocytes suggests that under their influence, these cells may express all the surface molecules required for antigen presentation and/or for being recognized as target cells in the context of thyroid autoimmune disease.  相似文献   
52.
Submitral ventricular aneurysm is a thoroughly studied pathology but is not well known due to its rarity. Clinically, it is manifested by symptoms and signs of heart failure, mitral regurgitation and/or ventricular arrhythmias, and may be associated with thromboembolic phenomena and myocardial ischemia due to compression of the coronary arteries by the aneurysm. A rare complication of this type of aneurysm is rupture into the left atrium. Transthoracic echocardiography plays an important role in the definitive diagnosis of this pathology, although the role of transesophageal echocardiography in the evaluation of these patients is less known. We report a case of a submitral ventricular aneurysm complicated by rupture into the left atrium, which was diagnosed by transesophageal echocardiography.  相似文献   
53.
Three cases with suspected pulmonary artery embolism are presented, in which transesophageal echocardiography showed a mass in the right pulmonary artery consistent with thrombus. The relevant diagnostic contributions of transesophageal echocardiography are discussed.  相似文献   
54.
55.
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   
56.
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   
57.
58.
Summary In this study, the largest Nordic study of its kind, investigated psychosexual dysfunction among subjects aged 55–57 years. The cohort included 862 subjects of both sexes and all were interviewed using the Diagnostic Interview Schedule (DIS). Results showed that 122 subjects had a lifetime diagnosis of psychosexual dysfunction. The lifetime prevalence of psychosexual dysfunction was 14.4%; of inhibited sexual desire, 9.8%; of inhibited sexual excitement, 3.5%; of inhibited orgasm, 2.1%; and of functional dyspareunia, 1.3%. Of the subjects with psychosexual dysfunction, 73% were women. The frequency was highest in those who had never married. Separated subjects had rates intermediate between the married and the never-married. The majority (76%) of affected subjects had only one dysfunction. However, 57% of them had received another psychiatric diagnosis at some time. Subjects with psychosexual dysfunction wereless frequently diagnosed as suffering from alcohol abuse and dependence and social phobia than subjects with no psychosexual dysfunction.  相似文献   
59.
The authors give an account of 190 premature infants they treated in 1956-1988, suffering from retinopathy of prematurity--ROP, and for prolonged subsequent periods. As the head of the team followed up all the children, there is an integrated view of the problem. The birth weight of the infants was 640 g--1,900 g. From the total number 76.8% infants had a birth weight of 1,500 g or less, 13.7% had a birthweight of 1,000 g or less. Evidence of the increasing rate is provided by the number of patients treated since birth at the department for premature and pathological infants FNM as well as by the number of children admitted from other departments after development of ROP. In 1956-1970, i. e. in 15 years, the authors looked after 34 patients, in 1971-1988, i. e. in 18 years there were 156 children with ROP. In 1956-70 cases of ROP predominated which developed as a result of absolute or relative hypoxia. They were successfully treated by individually adjusted and carefully controlled oxygen therapy (6.9% blind children). In 1971-1975 the possibility to use this therapy declined briskly because after introduction of modern medical technique the number of findings suggesting a hyperoxic insult increased. At that time the results deteriorated greatly (50% blind children). In 1976-1980 the results were favourably influenced by individual dosage of oxygen therapy in all infants, based on regular monitoring of blood gases (10.5% blind children).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
60.
The presence of vascular permeability factors in the extracellular products (ECP) of 10 strains of Renibacterium salmoninarum with different geographical origin and serological characteristics are reported. All the ECP produced haemorrhagic and/or oedematous zones at the injection site with a diameter ranging from 10-30 mm. However, the ECP samples did not display toxic effect in fish at the same dose as inoculated in rabbit (180-400 micrograms protein/0.1 ml). No differences were observed in the production of this dermatotoxic factor between the two antigenic groups found in this microorganism. Whereas heating (80 and 100 degrees C/15 min) the ECP samples resulted in a complete loss of their proteolytic activity, only a decrease (but not total inactivation) of the dermatotoxic effects was detected. Therefore, although proteases could be implicated in the permeability factor, they are not totally responsible for this activity.  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