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   27195篇
  免费   1355篇
  国内免费   173篇
耳鼻咽喉   233篇
儿科学   559篇
妇产科学   281篇
基础医学   3551篇
口腔科学   497篇
临床医学   1654篇
内科学   7223篇
皮肤病学   758篇
神经病学   1914篇
特种医学   1167篇
外科学   4572篇
综合类   163篇
预防医学   641篇
眼科学   873篇
药学   1728篇
中国医学   68篇
肿瘤学   2841篇
  2023年   157篇
  2022年   335篇
  2021年   539篇
  2020年   297篇
  2019年   388篇
  2018年   546篇
  2017年   426篇
  2016年   525篇
  2015年   558篇
  2014年   822篇
  2013年   898篇
  2012年   1555篇
  2011年   1743篇
  2010年   962篇
  2009年   867篇
  2008年   1510篇
  2007年   1689篇
  2006年   1661篇
  2005年   1790篇
  2004年   1803篇
  2003年   1843篇
  2002年   1706篇
  2001年   430篇
  2000年   359篇
  1999年   454篇
  1998年   450篇
  1997年   354篇
  1996年   336篇
  1995年   293篇
  1994年   276篇
  1993年   241篇
  1992年   287篇
  1991年   269篇
  1990年   251篇
  1989年   223篇
  1988年   205篇
  1987年   175篇
  1986年   168篇
  1985年   169篇
  1984年   155篇
  1983年   105篇
  1982年   94篇
  1981年   92篇
  1980年   84篇
  1979年   82篇
  1978年   72篇
  1977年   63篇
  1976年   47篇
  1975年   40篇
  1974年   44篇
排序方式: 共有10000条查询结果,搜索用时 343 毫秒
971.
A female infant born at 36 weeks gestational age with birthweight 2135 g, and who developed respiratory disorder, hyperlactacidemia and hypertrophic cardiomyopathy after birth, was admitted to hospital at 3 days of age. After admission, bilious emesis, abdominal distention, and passage disorder of the gastrointestinal tract were resistant to various drugs. Exploratory laparotomy was performed at 93 days of age, but no organic lesions were identified and normal Meissner/Auerbach nerve plexus was confirmed, which led to a clinical diagnosis of chronic intestinal pseudo‐obstruction (CIPO). She was diagnosed with mitochondrial respiratory chain complex IV deficiency on histopathology of the abdominal rectus muscle and enzyme activity measurement. This is the first report of a neonate with mitochondrial respiratory chain complex deficiency with intractable CIPO. CIPO can occur in neonates with mitochondrial respiratory chain disorder, necessitating differential diagnosis from Hirschsprung disease.  相似文献   
972.
We report the case of an 11‐year‐old boy who was diagnosed with catecholaminergic polymorphic ventricular tachycardia (CPVT). The patient had a medical history of three episodes of syncope. The last episode was cardiac arrest while swimming. After resuscitation using automated external defibrillator, he was placed under cerebral hypothermia, examined for long QT syndrome, and underwent insertion of implantable cardioverter defibrillator. He was subsequently discharged from hospital without any adverse sequelae. The patient was diagnosed with CPVT after detection of ryanodine receptor 2 mutation. His father also carried the same mutation, although he did not have any symptoms nor did he have a history of syncope. We propose that CPVT should be included in the differential diagnosis in children with recurrent episodes of syncope.  相似文献   
973.

Background

Few studies have examined how renin–angiotensin system inhibitors (RASI) delay dialysis initiation in patients with advanced chronic kidney disease (CKD). We conducted a retrospective survey to examine this subject.

Methods

We reviewed the records of patients with advanced CKD for the 60-month period before dialysis initiation between 1990 and 2015. Patients were classified based on the decade of dialysis initiation into the 1990s, 2000s, and 2010s groups. The rates of antihypertensive medications administered were assessed. The rate of decline of renal function was evaluated by the slope of reciprocal serum creatinine (SRSC). Multiple regression analyses were conducted to evaluate factors contributing to renoprotection.

Results

The duration of RASI administration was longer in the 2010s than in 2000s and 1990s. Both diabetic and non-diabetic patients had lower SRSC in the 2010s compared to the 2000s. In the 2010s, the rate of RASI administration during the 60-month pre-dialysis period showed an initial rise followed by a downward trend, although the rates of administration of the other classes of antihypertensives increased continuously. Multivariate regression analyses identified age, blood pressure, diuretics, α-blockers, α-methyldopa and RASI as independent predictors of SRSC in the 2010s. The rate of RASI administration correlated with serum potassium concentration.

Conclusion

Our findings suggest that in the 2010s, RASI with other antihypertensive agents contributed to renoprotection in advanced CKD patients, but they were underused because of the concern over hyperkalemia. In real-world clinical practice, physicians may feel great hesitation in using RASI in patients with advanced CKD.
  相似文献   
974.
A 66-year-old female, under regular follow-up for 20 years after aortic valve replacement (19-mm Carbomedics), presented dyspnea on effort and hypotension during hemodialysis. A transthoracic echocardiogram showed elevation of transvalvular velocity up to 4 m/s, but the structure around the aortic prosthesis was difficult to observe due to artifacts. Fluoroscopy revealed normal motion of the leaflets of the mechanical valve. Intracardiac echocardiography (ICE) revealed a pannus-like structure in the left ventricular outflow tract. Transesophageal echocardiogram also revealed this structure. ICE can visualize structural abnormalities around a prosthetic valve after cardiac surgery even in patients in whom conventional imaging modalities failed.  相似文献   
975.
976.
977.
978.
979.
980.
Langerhans cells (LCs) represent a special subset of immature dendritic cells (DCs) that reside in epithelial tissues at the environmental interfaces. Although dynamic interactions of mature DCs with T cells have been visualized in lymph nodes, the cellular behaviours linked with the surveillance of tissues for pathogenic signals, an important function of immature DCs, remain unknown. To visualize LCs in situ, bone marrow cells from C57BL/6 mice expressing the enhanced green fluorescent protein (EGFP) transgene were transplanted into syngeneic wild-type recipients. Motile activities of EGFP(+) corneal LCs in intact organ cultures were then recorded by time lapse two-photon microscopy. At baseline, corneal LCs exhibited a unique motion, termed dendrite surveillance extension and retraction cycling habitude (dSEARCH), characterized by rhythmic extension and retraction of their dendritic processes through intercellular spaces between epithelial cells. Upon pinpoint injury produced by infrared laser, LCs showed augmented dSEARCH and amoeba-like lateral movement. Interleukin (IL)-1 receptor antagonist completely abrogated both injury-associated changes, suggesting roles for IL-1. In the absence of injury, exogenous IL-1 caused a transient increase in dSEARCH without provoking lateral migration, whereas tumour necrosis factor-alpha induced both changes. Our results demonstrate rapid cytokine-mediated behavioural responses by LCs to local tissue injury, providing new insights into the biology of LCs.  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