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   15178篇
  免费   863篇
  国内免费   69篇
耳鼻咽喉   130篇
儿科学   307篇
妇产科学   469篇
基础医学   1865篇
口腔科学   517篇
临床医学   1224篇
内科学   4315篇
皮肤病学   376篇
神经病学   1364篇
特种医学   310篇
外科学   2215篇
综合类   100篇
一般理论   2篇
预防医学   1096篇
眼科学   214篇
药学   804篇
中国医学   76篇
肿瘤学   726篇
  2023年   143篇
  2022年   307篇
  2021年   639篇
  2020年   329篇
  2019年   521篇
  2018年   682篇
  2017年   403篇
  2016年   412篇
  2015年   472篇
  2014年   711篇
  2013年   823篇
  2012年   1300篇
  2011年   1318篇
  2010年   666篇
  2009年   598篇
  2008年   1016篇
  2007年   935篇
  2006年   906篇
  2005年   875篇
  2004年   777篇
  2003年   616篇
  2002年   608篇
  2001年   69篇
  2000年   74篇
  1999年   86篇
  1998年   98篇
  1997年   64篇
  1996年   73篇
  1995年   60篇
  1994年   47篇
  1993年   38篇
  1992年   38篇
  1991年   27篇
  1990年   23篇
  1989年   21篇
  1988年   23篇
  1987年   15篇
  1986年   27篇
  1985年   23篇
  1984年   25篇
  1983年   19篇
  1982年   25篇
  1981年   22篇
  1980年   24篇
  1979年   9篇
  1978年   12篇
  1976年   8篇
  1974年   12篇
  1973年   19篇
  1972年   10篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
We thank Dr Villata et al. for their thought-provoking comments.Their concern about the suitableness to choose combined endpointsin clinical trials deserves some comment.  相似文献   
52.
We report the case of a patient who was operated on in February 2001. We performed a wedge resection of the upper right lobe. The pathologic examination demonstrated a lung adenocarcinoma (pT2N0M0, R0). We used staple line reinforcement material (ePTFE) during the operation because the patient had an important emphysema. We re-operated in January 2005 because during follow-up we observed a suspicious image that suggested a tumoral relapse. Histopathological study showed extrinsic material compatible with the one used in the original resection.  相似文献   
53.
54.
Resumen La técnica del cultivo celular es la que ha permitido conocer el comportamientoin vitro de las células cancerosas. En esta revisión pretendemos introducir las peculiaridades básicas del cultivo celular, referido especialmente a líneas cancerosas mamarias, relacionar el origen de las líneas celulares más utilizadas en la investigación de este cáncer, mencionar las técnicas de laboratorio que pueden aplicarse sobre estos cultivos y ejemplificar la utilidad de las mismas, tomando como modelo diversos trabajos que estudian los efectos del factor de crecimiento epidérmico sobre líneas celulares hormonoindependientes de cáncer de mama.   相似文献   
55.
56.
Tissue ischemia, necrosis, and gangrene are uncommon but well-described complications of arterial catheterization in the neonate. Treatment options for progressive tissue necrosis following arterial embolization and/or vasospasm are limited in these patients secondary to unpredictable pharmacokinetics and risks associated with systemic anticoagulation or vasodilatation in newborns. We report a case of a multidose regimen of topical 2% nitroglycerin ointment for reversing severe tissue ischemia following peripheral arterial line placement. The favorable response in this infant suggests that topical nitroglycerin therapy should be considered as potential therapy to ameliorate the effects of vascular compromise following arterial line placement in neonates.  相似文献   
57.
Ischemic stroke occurs in 0.2-0.4% of patients undergoing left heart catheterization, and is responsible for 5-10% of the mortality associated with the procedure. The main predisposing factors for this complication are female gender, complex atherosclerotic plaques in the ascending aorta, and peripheral arterial disease. The possibility of timely intervention with reperfusion therapy supports close clinical monitoring during the immediate post-catheterization period. The cardiologist should be familiar with the various types of stroke reperfusion therapy and its indications according to the time interval between catheterization and the stroke. The decision should be discussed with neurology and neuroradiology.  相似文献   
58.
Familial hypercholesterolaemia is a frequent, inherited, monogenic disorder, associated with accelerated development of atherosclerotic disease leading to coronary artery disease. Life expectancy of patients with familial hypercholesterolaemia is reduced by 15-30 years unless they are adequately treated with lipid-lowering therapy. Given the chronic nature of this disease, the selection of a therapeutic approach should be strongly based on its long-term safety and tolerability. The introduction of HMG-CoA reductase inhibitors has revolutionised the treatment of familial hypercholesterolaemia.Simvastatin 40-80 mg/day effectively reduces serum low density lipoprotein (LDL)-cholesterol levels. Furthermore, simvastatin reduces triglycerides and mildly raises high density lipoprotein-cholesterol levels. In addition to the hypolipidaemic effect, other potentially important effects, such as improvement of endothelial function and reduction of LDL oxidation and vascular inflammation, have been associated with HMG-CoA reductase inhibitor therapy. Simvastatin has also been shown to abolish the progression, and even facilitate the regression, of existing human atherosclerotic lesions.The good safety and tolerability profile of simvastatin is clearly highlighted by the low rate of therapy discontinuation observed in several population-based clinical trials. The most common adverse events leading to the discontinuation of therapy are gastrointestinal upset and headache. Asymptomatic elevations in liver transaminase levels and myopathy are uncommon.The overwhelming clinical evidence regarding the long-term use of HMG-CoA reductase inhibitor therapy in patients with familial hypercholesterolaemia together with the long-term safety data (particularly relating to simvastatin) provide support for the use of this drug as a first-line agent when pharmacological treatment is indicated. Early intervention with simvastatin treatment can be successfully implemented with favourable economic benefits.  相似文献   
59.
CD24 expression on human keratinocytes   总被引:4,自引:0,他引:4  
Abstract: CD24 or Nectadrin is a cell surface glycoprotein expressed in pre-B lymphocytes, T lymphocytes, neurons, muscle cells and carcinoma cells. Its function is not completely known, but it has been suggested that it is involved in cell adhesion and signalling. CD24 has recently been identified as the human molecule homologous to the murine heat-stable antigen (HSA). HSA is expressed by murine keratinocytes and delivers costimulatory signals in T-cell activation. Long-term cultures of normal human keratinocytes (HKC) were obtained from skin of human female breast sections and either left untreated or were treated with phorbol-12-myristate-13-acetate (PMA) at 10–100 ng/ml, calcium 0.5–2 mM or IFN-γ 100–1000 U/ml, for 24–48 h. Using RT-PCR and flow cytometry we showed that HKC express low levels of CD24 even under basal conditions, and the treatment with calcium, PMA or IFN-γ increased levels of CD24 mRNA and protein. To the best of our knowledge, this is the first report to measure CD24 expression and production by cultured HKC in basal conditions and after stimulation. Further studies are needed to determine biological and therapeutical relevance of these findings.  相似文献   
60.
A novel method for estimating the susceptibility of an object by using the magnetic resonance (MR) imaging field distortions in an external-reference water bath next to the object is described. The field measurement was obtained with a phase reconstruction from a gradient-echo acquisition. A field model of an arbitrary object in a static magnetic field was discretely calculated from geometry determined from the magnitude reconstruction. Least-squares estimation yields the susceptibility of the object. Required (and proven) assumptions include validity of superposition, object homogeneity, negligible higher-order field terms, field-model accuracy, geometric-model accuracy, and correlation of gradient-echo phase to field distortion. MR susceptometry estimation of phantoms yielded susceptibility estimates that correlated well with known values (r >.9975). This MR susceptometry method is a first step toward quantitation of iron levels through MR imaging phase information in patients with iron overload.  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