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   5957篇
  免费   270篇
  国内免费   17篇
耳鼻咽喉   34篇
儿科学   147篇
妇产科学   94篇
基础医学   753篇
口腔科学   291篇
临床医学   456篇
内科学   1202篇
皮肤病学   153篇
神经病学   454篇
特种医学   234篇
外科学   983篇
综合类   40篇
一般理论   5篇
预防医学   405篇
眼科学   100篇
药学   464篇
中国医学   3篇
肿瘤学   426篇
  2023年   18篇
  2022年   43篇
  2021年   88篇
  2020年   68篇
  2019年   89篇
  2018年   99篇
  2017年   112篇
  2016年   119篇
  2015年   108篇
  2014年   190篇
  2013年   294篇
  2012年   378篇
  2011年   381篇
  2010年   219篇
  2009年   225篇
  2008年   338篇
  2007年   337篇
  2006年   370篇
  2005年   348篇
  2004年   320篇
  2003年   326篇
  2002年   307篇
  2001年   50篇
  2000年   45篇
  1999年   57篇
  1998年   77篇
  1997年   70篇
  1996年   67篇
  1995年   62篇
  1994年   54篇
  1993年   55篇
  1992年   41篇
  1991年   43篇
  1990年   49篇
  1989年   41篇
  1988年   50篇
  1987年   33篇
  1986年   33篇
  1985年   45篇
  1984年   43篇
  1983年   39篇
  1982年   48篇
  1981年   32篇
  1980年   35篇
  1979年   29篇
  1978年   37篇
  1977年   33篇
  1976年   21篇
  1975年   27篇
  1973年   24篇
排序方式: 共有6244条查询结果,搜索用时 0 毫秒
81.
The clinical course and coronary arteriographic findings in eight patients with Prinzmetal's variant angina pectoris are reviewed and contrasted to previously reported cases. In six patients with S-T-elevation inferiorly, three had normal coronary arteriograms, one had complete right coronary artery occlusion, one had diffuse triple-vessel disease, and one did not undergo coronary arteriography. In two patients with S-T-elevation anteriorly, severe stenosis of the anterior descending coronary artery was present. Medical treatment in four patients and surgical revascularization of the anterior descending coronary artery in two patients were both accompanied by marked symptomatic improvement. Spontaneous loss of angina occurred in two patients. During 17 months' mean follow-up, seven patients have remained free of angina and one died suddenly. Variant angina pectoris may be accompanied by a variety of coronary arteriographic findings and the prognosis appears more favorable than previously reported.  相似文献   
82.
BACKGROUND/AIMS: Steatosis is common in patients with hepatitis C virus (HCV) infection. Its influence on disease progression is only partially understood. The aim of this study was to evaluate the impact of steatosis on fibrosis progression over time in relation to HCV genotype. METHODS: We retrospectively analyzed 98 patients who underwent dual liver biopsies prior to antiviral treatment. The median follow-up time was 5.8 years. Biopsy specimens were assessed for necroinflammatory activity, fibrosis and steatosis. RESULTS: The prevalence and grade of steatosis were strongly associated with HCV genotype 3, independent of sex, age, body mass index and alcohol consumption. Progressive fibrosis was more prevalent in patients whose initial biopsy showed steatosis, an effect seen mainly in genotype 3 infected patients. Low-grade steatosis was observed in overweight patients, but high-grade steatosis was associated with genotype 3, independent of body mass index. CONCLUSIONS: Our data confirm the association between HCV genotype 3 and steatosis. Furthermore, we showed that steatosis in genotype 3 infected patients is a risk factor for progression of fibrosis. Therefore, patients with genotype 3 and steatosis ought to be recommended for early therapeutic intervention.  相似文献   
83.
OBJECTIVE: In this study of female home care personnel employed in a municipality (n = 643; participation rate 94%) we investigated (1) the prevalence of tender points and fibromyalgia (FM); (2) the relationships between tender point score and other signs and symptoms; (3) if subgroups based on the tender point score differed with respect to signs, symptoms, disability, and health related quality of life; and (4) signs that showed the strongest intercorrelations with disability and health. METHODS: The following variables were registered: (1) Signs: joint mobility, spinal posture and mobility, tender points, and segmental mobility and pain provocation at L4-S1 levels of the low back. (2) Symptoms: pain and pain intensity and other symptoms. (3) Disability (i.e., self-rated reduced capacity for everyday activities and employment) and health: 3 indices and sick leave. RESULTS: The tender point score correlated with the number of pain regions and the pain intensities, and the amount of other symptoms, sick leave, and disability. Tender point score was the strongest regressor of the investigated signs in regression of the 2 disability indices. Segmental pain showed the strongest correlation with tender point score. Three subgroups identified by tender point score showed significant differences in segmental pain, prevalence and intensity of different symptoms, disability, and health related quality of life. The prevalence of FM was 2.0%. CONCLUSION: Tender point score together with different symptoms showed relatively strong correlations with disability. A relatively high prevalence of FM was found in occupationally active female home care personnel.  相似文献   
84.
The activity of eosinophils and neutrophils with respect to the release of granule proteins was studied in 11 patients with the hypereosinophilic syndrome (HES). Granulocytes or purified eosinophils were stimulated with serum-opsonized Sephadex particles (C3b-induced release), and the released amounts of eosinophil cationic protein (ECP), eosinophils protein-X (EPX) and myeloperoxidase (MPO) were measured by means of specific radioimmunoassays (RIA). Eosinophils obtained from patients with HES released significantly more ECP ( P <0·002) and EPX ( P <0·01) after 20 min of incubation than cells from the control group. The cellular content of ECP and EPX in eosinophils obtained from the patients with HES was significantly reduced to 50% and 62%, respectively, of the content of these granule proteins of eosinophils from the control group. In separated eosinophils light-density eosinophils released more of both ECP and EPX than normal density eosinophils. There was no difference in MPO release between the patients and the control group. We conclude that the eosinophils from patients with HES have an increased propensity to release their granule proteins and the releasability seems to be related to the density of the cells.  相似文献   
85.
Failure of rapid atrial pacing in the conversion of atrial flutter   总被引:2,自引:0,他引:2  
Rapid atrial pacing, at rates of 150 to 600/min with stimulus strength up to 15 ma, was attempted in 15 patients with atrial flutter. In 13 of the patients, atrial capture was achieved with changes in both atrial and ventricular rates. In 7 of these, flutter resumed upon cessation of pacing. In the other 6, rapid atrial pacing produced atrial fibrillation which persisted until cardioversion. In 2 patients, atrial capture could not be obtained because of increased atrial refractoriness secondary to flutter. Thus, rapid atrial pacing was ineffective in converting atrial flutter to normal sinus rhythm in all 15 patients. This was in contrast to direct-current cardioversion which was successful in 12 of the patients, in all of whom stable sinus rhythm developed. The 3 patients who did not undergo cardioversion subsequently experienced spontaneous conversion to sinus rhythm. These results suggest that rapid atrial pacing has little place in the management of atrial flutter.  相似文献   
86.
Thirty-seven patients in cardiogenic shock due to acute myocardial infarction were treated with intraaortic balloon counterpulsation and/or surgery. Eighteen of these patients were treated with counterpulsation alone; eight survived and five were in functional class I or II at the time of follow-up; two were in functional class III, and one was in functional class IV. Nineteen patients were treated surgically, eight survived and seven were in functional class I or II at the time of follow-up; one was in functional class III. Good functional recovery with counterpulsation alone is most common with inferior infarction. With surgery, functional recovery depends not only on the extent of the infarction and the coronary anatomy, but also on the ability to perform surgery within 12 hours of infarction or to support the patient with mechanical means for 10 to 14 days after the infarction and then perform surgery.  相似文献   
87.
Granzymes are serine proteases known mostly for their role in the induction of apoptosis. Granzymes A and B have been extensively studied, but relatively little is known about granzymes C to G and K to M. T cells, lymphohematopoietic stromal cells, and granulated metrial gland cells express granzyme D, but the function of granzyme D is unknown. Here we show that granzyme D is expressed by murine mast cells and that its level of expression correlates positively with the extent of mast cell maturation. Coculture of mast cells with live, Gram-positive bacteria caused a profound, Toll-like receptor 2 (TLR2)-dependent induction of granzyme D expression. Granzyme D expression was also induced by isolated bacterial cell wall components, including lipopolysaccharide (LPS) and peptidoglycan, and by stem cell factor, IgE receptor cross-linking, and calcium ionophore stimulation. Granzyme D was released into the medium in response to mast cell activation. Granzyme D induction was dependent on protein kinase C and nuclear factor of activated T cells (NFAT). Together, these findings identify granzyme D as a novel murine mast cell protease and implicate granzyme D in settings where mast cells are activated, such as bacterial infection and allergy.  相似文献   
88.
89.
90.
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