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   55347篇
  免费   5166篇
  国内免费   3514篇
耳鼻咽喉   539篇
儿科学   663篇
妇产科学   459篇
基础医学   6459篇
口腔科学   852篇
临床医学   6678篇
内科学   8981篇
皮肤病学   690篇
神经病学   3100篇
特种医学   2524篇
外国民族医学   19篇
外科学   5839篇
综合类   8882篇
现状与发展   14篇
一般理论   7篇
预防医学   3514篇
眼科学   1365篇
药学   5874篇
  51篇
中国医学   2838篇
肿瘤学   4679篇
  2024年   158篇
  2023年   768篇
  2022年   1978篇
  2021年   2693篇
  2020年   1992篇
  2019年   1771篇
  2018年   1847篇
  2017年   1701篇
  2016年   1828篇
  2015年   2641篇
  2014年   3152篇
  2013年   3120篇
  2012年   4453篇
  2011年   4744篇
  2010年   3415篇
  2009年   2625篇
  2008年   3179篇
  2007年   3162篇
  2006年   2860篇
  2005年   2805篇
  2004年   2041篇
  2003年   2127篇
  2002年   1793篇
  2001年   1313篇
  2000年   1018篇
  1999年   966篇
  1998年   574篇
  1997年   562篇
  1996年   373篇
  1995年   435篇
  1994年   308篇
  1993年   188篇
  1992年   274篇
  1991年   196篇
  1990年   166篇
  1989年   172篇
  1988年   116篇
  1987年   123篇
  1986年   119篇
  1985年   61篇
  1984年   40篇
  1983年   21篇
  1982年   25篇
  1981年   16篇
  1980年   15篇
  1979年   15篇
  1974年   8篇
  1973年   13篇
  1972年   9篇
  1969年   12篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Struma ovarii, a rare varity of ovarian neoplasm, belongs to the group of monodermic teratomas mainly composed of thyroid tissue. The preoperative diagnosis is always difficult to identify without histopathological examination. Surgery is the only treatment because malignant alteration is possible and thyroid hyperactivity or hyperthyroidism may occur. Our patient, a post-menopausal women, had unilateral, large, multiloculated ovary mass of 20cm×15cm×10cm size without any thyroid hyper activity. The radical excision of the tumor with right ovary was preformed. Histopathological examination confirmed struma ovarii. The post-operative period was uneventful and her thyroid function remained normal.  相似文献   
992.
993.
994.
目的:为深入分析研究本草纲目中的药物警戒思想提供新方法。方法:基于本草纲目金陵本文献著作设计了药物警戒数据库,阐述了数据库建立的要求和存储模型的选取,以及数据库的概念和逻辑设计。结果:在此数据库的基础上可建立知识发现系统,应用数据挖掘算法,对本草纲目中的药物警戒思想进行分析。结论:本草纲目药物警戒思想数据库的建立可以为深入研究药物警戒思想提供方便、准确的手段,此方法也可应用于其他文献著作研究。  相似文献   
995.
996.
To examine the potential roles of melatonin in drought tolerance, we tested the effects of its long‐term exogenous application on ‘Hanfu’ apple (Malus domestica Borkh.). When 100 μm melatonin was added to soils under drought conditions, the resultant oxidative stress was eased and leaf senescence was delayed. This molecule significantly reduced chlorophyll degradation and suppressed the up‐regulation of senescence‐associated gene 12 (SAG12) and pheophorbide a oxygenase (PAO). Such treatment also alleviated the inhibition of photosynthesis brought on by drought stress. We also investigated quenching and the efficiency of Photosystem II (PSII) photochemistry under dark and light conditions and found that melatonin helped to maintain better function of PSII under drought. The addition of melatonin also controlled the burst of hydrogen peroxide, possibly through direct scavenging and by enhancing the activities of antioxidative enzymes and the capacity of the ascorbate–glutathione cycle. Thus, understanding this effect of melatonin on drought tolerance introduces new possibilities to use this compound for agricultural purposes.  相似文献   
997.
Plate‐like osteoma cutis (PLOC) is a dermatological disorder characterized by superficial ossification and rarely occurs without any underlying tissue abnormalities or pre‐existing calcification. The hereditary form of PLOC is mainly due to inactivating mutation in the GNAS gene. Inactivating mutation of the GNAS gene is associated with several diseases, which commonly manifest heterotopic ossification and hormonal resistance; however, the development of malignant neoplasm has never been reported. Herein, we report a case of a patient with a novel nonsense mutation in the GNAS gene, who presented with concurrent PLOC and medulloblastoma.  相似文献   
998.
999.
The aim of this study is to evaluate the utility of acoustic radiation force impulse (ARFI) elastography for assessing hepatic fibrosis stage and non-alcoholic fatty liver disease (NAFLD) severity, as well as the relationship among hepatic histologic changes using shear wave velocity (SWV). Animal models with various degrees of NAFLD were established in 110 rats. The right liver lobe was processed and embedded in a fabricated gelatin solution (porcine skin). Liver mechanics were measured using SWV induced by acoustic radiation force. Among the histologic findings, liver elasticity could be used to differentiate normal rats from rats with simple steatosis (SS) as well as distinguish SS from non-alcoholic steatohepatitis (NASH), with areas under the receiver operating characteristic curves (AUROC) of 0.963 (95% confidence interval = 0.871–0.973) and 0.882 (95% confidence interval = 0.807–0.956), respectively. For NAFLD rats, the diagnostic performance of ARFI elastography in predicting significant fibrosis (F ≥ 2) had an AUROC of 0.963. For evaluating steatosis severity, we found a progressive increase in ARFI velocity proportional to steatotic severity in NAFLD rat models, but we observed no significant differences for steatotic severity after excluding the rats with fibrosis. ARFI elastography may be used to differentiate among degrees of severity of NAFLD and hepatic fibrotic stages in NAFLD rat models.  相似文献   
1000.
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