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   199773篇
  免费   2268篇
  国内免费   70篇
耳鼻咽喉   1490篇
儿科学   8430篇
妇产科学   3581篇
基础医学   19320篇
口腔科学   1994篇
临床医学   13709篇
内科学   35238篇
皮肤病学   1655篇
神经病学   17477篇
特种医学   9814篇
外科学   32406篇
综合类   3233篇
一般理论   10篇
预防医学   19285篇
眼科学   4072篇
药学   11524篇
中国医学   772篇
肿瘤学   18101篇
  2023年   168篇
  2022年   449篇
  2021年   823篇
  2020年   445篇
  2019年   540篇
  2018年   22498篇
  2017年   17714篇
  2016年   20067篇
  2015年   1504篇
  2014年   1738篇
  2013年   1845篇
  2012年   8399篇
  2011年   22475篇
  2010年   19572篇
  2009年   12122篇
  2008年   20563篇
  2007年   22824篇
  2006年   1582篇
  2005年   3145篇
  2004年   4235篇
  2003年   5145篇
  2002年   3211篇
  2001年   974篇
  2000年   1077篇
  1999年   744篇
  1998年   435篇
  1997年   374篇
  1996年   227篇
  1995年   231篇
  1994年   206篇
  1993年   185篇
  1992年   389篇
  1991年   471篇
  1990年   461篇
  1989年   431篇
  1988年   358篇
  1987年   314篇
  1986年   289篇
  1985年   307篇
  1984年   237篇
  1983年   201篇
  1980年   137篇
  1979年   243篇
  1978年   166篇
  1977年   151篇
  1976年   143篇
  1975年   168篇
  1974年   173篇
  1973年   177篇
  1972年   138篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Spontaneous gall bladder perforation in infants is rare. We report a 3-month-old male infant who presented with progressive abdominal distension, low-grade fever, bilateral hydrocele and acholic stools. Ultrasonography showed free fluid in the peritoneal cavity, which was bile-stained on paracentesis. Surgical exploration revealed sterile biliary peritonitis and a gangrenous gall bladder. Partial cholecystectomy with external biliary drainage resulted in satisfactory recovery.  相似文献   
92.
Conclusion In the year 2003 there is no “one best bariatric operation” for every severely obese patient. The choice of operation must be tailored to each individual patient’s needs and wishes. For the superobese patient, the patient diagnosed with intestinal metaplasia of the stomach, and for those patients who do not wish to undergo the severe dietary restrictions imposed by the RNY-GB, the BPD-DS is a valuable surgical option.  相似文献   
93.
Depressive symptoms in older adults are common, but the minority of elderly meet criteria for major depressive disorder. This has led to confusion regarding the recognition of diagnosis, approach to treatment, and monitoring of outcomes in this needy population. Few depressed older adults are willing to seek treatment from psychiatrists or mental health specialists. Treatment approaches to the depressive spectrum of disorders in late life, which encompasses major and minor depressive disorder, dysthymic disorder, and mood disorders related to medical conditions, must include evidence-based algorithms that can be delivered in a variety of health care settings. Several recent multisite trials have advanced the use of collaborative care models and the systematic stepwise approach to the treatment of depression and anxiety states in older adults. This offers the ability to provide effective treatment of depression for older adults, consistent with current guidelines, in primary care and specialized health care settings.  相似文献   
94.
95.
96.
97.
98.
Purpose Reelin is important in the guidance of neuronal stem cells in the central nervous system during normal development. We wished to determine whether reelin is expressed in the retina and cornea after injury. Methods Mice underwent laceration of their retina as well as corneal epithelial debridement. The mice were sacrificed at 3 days, and eyes were fixed and stained for reelin expression and reelin messenger ribonucleic acid (mRNA). Results In normal eyes, reelin was expressed only at very low levels in the ganglion cell layer of the retina and the endothelial cell layer of the cornea. In injured eyes, there was marked expression in reelin immunoreactivity in the retina and cornea. Reelin gene expression was seen in the retina and cornea. Conclusions Reelin is expressed during normal retinogenesis. This study shows that reelin is also upregulated following injury to the retina and cornea. The expression of reelin following injury suggests that reelin may play an important role in regulating stem cell trafficking in neuronal and nonneuronal tissues following injury similar to its role in normal organogenesis. For consideration of publication in Graefe’s Archive for Clinical and Experimental Ophthalmology.  相似文献   
99.
Background A recombinant form of the α2(IV)NC1 domain of type IV collagen has been shown to have potent anti-angiogenic activity although this peptide has not been studied in the context of proliferative retinopathies. In the current investigation we examined the potential for α2(IV)NC1 to regulate retinal microvascular endothelial cell function using a range of in vitro and in vivo assay systems. Materials and methods α2(IV)NC1 at concentrations between 0.1 and 1 μg/ml was added to retinal microvascular endothelial cells (RMECs) followed by assessment of cell attachment, proliferation and survival. This agent was also tested within a novel in vitro three-dimensional retinal angiogenesis assay and the number of angiogenic sprouts quantified. α2(IV)NC1 was also delivered intra-vitreally to mice with oxygen-induced proliferative retinopathy (OIR) and neovascularisation evaluated in comparison with vehicle-treated controls. Results RMECs treated with α2(IV)NC1 (0.1, 0.5 and 1 μg/ml) showed delayed attachment at 3 h post-seeding, although this deficit had been restored at the 6-h time point. BrdU assay of DNA replication revealed that confluent RMECs treated with α2(IV)NC1 showed no measurable response in comparison with vehicle-treated controls. By contrast, proliferation of sub-confluent RMECs was significantly reduced by α2(IV)NC1 at 0.5 μg/ml (P<0.01). α2(IV)NC1 also induced apoptosis in RMECs and inhibited angiogenesis of pre-existing retinal vascular networks in vitro (P<0.001). Intra-vitreal injection of α2(IV)NC1 in the OIR model significantly inhibited pre-retinal neovascularisation compared with vehicle-treated controls (P<0.001). Conclusion α2(IV)NC1 inhibits angiogenesis in the retinal microvasculature. This recombinant protein has potential for the treatment of neovascularisation in proliferative retinopathies. BioStratum Inc. did not sponsor this research in any way. None of the authors are paid consultants with this company.  相似文献   
100.
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