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   13044篇
  免费   2711篇
  国内免费   133篇
耳鼻咽喉   403篇
儿科学   293篇
妇产科学   321篇
基础医学   717篇
口腔科学   510篇
临床医学   3155篇
内科学   2674篇
皮肤病学   409篇
神经病学   961篇
特种医学   418篇
外科学   1725篇
综合类   367篇
现状与发展   2篇
预防医学   2117篇
眼科学   167篇
药学   565篇
  1篇
中国医学   144篇
肿瘤学   939篇
  2024年   65篇
  2023年   442篇
  2022年   172篇
  2021年   391篇
  2020年   578篇
  2019年   299篇
  2018年   684篇
  2017年   698篇
  2016年   730篇
  2015年   826篇
  2014年   843篇
  2013年   1246篇
  2012年   704篇
  2011年   648篇
  2010年   679篇
  2009年   759篇
  2008年   556篇
  2007年   494篇
  2006年   504篇
  2005年   381篇
  2004年   311篇
  2003年   239篇
  2002年   201篇
  2001年   277篇
  2000年   216篇
  1999年   222篇
  1998年   285篇
  1997年   308篇
  1996年   326篇
  1995年   265篇
  1994年   189篇
  1993年   133篇
  1992年   128篇
  1991年   122篇
  1990年   118篇
  1989年   118篇
  1988年   103篇
  1987年   79篇
  1986年   68篇
  1985年   66篇
  1984年   57篇
  1983年   57篇
  1982年   37篇
  1981年   48篇
  1980年   21篇
  1979年   15篇
  1978年   17篇
  1977年   15篇
  1976年   15篇
  1969年   21篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
目的 探讨在苯妥英钠(Phenytoin,PHT)促进大鼠牙周膜干细胞(Rat periodontal ligament stem cells,rPDLSCs)、大鼠骨髓间充质干细胞(Rat Bone Marrow Mesenchymal Stem Cells,rBMMSCs)黏附于牙骨质过程中,整合素α5β1(Integrin α5β1)起到的作用。方法 提取大鼠BMMSCs和PDLSCs,培养并纯化。通过细胞鉴定后,将获得的两种细胞各分为4组:40 mg/L PHT处理组、40 mg/L PHT+整合素α5抗体处理组、40 mg/L PHT+整合素β1抗体处理组、PBS处理组,每组细胞放入置有牙骨质片的96孔板处理4 h后,检测黏附于牙骨质片上的细胞量并做以比较。最后,利用qRT-PCR和Western blot检测40 mg/L PHT组与对照组细胞的整合素α5、β1亚基的mRNA与蛋白表达量。结果 40 mg/L PHT可促进rBMMSCs及rPDLSCs黏附于牙骨质片,加入整合素α5、β1抗体后,均明显抑制了40 mg/L PHT对rBMMSCs、rPDLSCs黏附于牙骨质的促进作用(P<0.01)。qRT-PCR、Western-blot结果显示PHT处理组的整合素α5、β1亚基表达量高于空白对照组(P<0.05)。结论 40 mg/L PHT能促进rBMMSCs、rPDLSCs黏附于牙骨质,该作用与整合素α5β1的表达上调密切相关。  相似文献   
4.
Melatonin, the main hormone produced by the pineal gland, is secreted in a circadian manner (24‐hr period), and its oscillation influences several circadian biological rhythms, such as the regulation of clock genes expression (chronobiotic effect) and the modulation of several endocrine functions in peripheral tissues. Assuming that the circadian synchronization of clock genes can play a role in the regulation of energy metabolism and it is influenced by melatonin, our study was designed to assess possible alterations as a consequence of melatonin absence on the circadian expression of clock genes in the epididymal adipose tissue of male Wistar rats and the possible metabolic repercussions to this tissue. Our data show that pinealectomy indeed has impacts on molecular events: it abolishes the daily pattern of the expression of Clock, Per2, and Cry1 clock genes and Pparγ expression, significantly increases the amplitude of daily expression of Rev‐erbα, and affects the pattern of and impairs adipokine production, leading to a decrease in leptin levels. However, regarding some metabolic aspects of adipocyte functions, such as its ability to synthesize triacylglycerols from glucose along 24 hr, was not compromised by pinealectomy, although the daily profile of the lipogenic enzymes expression (ATP‐citrate lyase, malic enzyme, fatty acid synthase, and glucose‐6‐phosphate dehydrogenase) was abolished in pinealectomized animals.  相似文献   
5.
Objective: To assess the quality of images and video clips of fetal central nervous (CNS) structures obtained by ultrasound and transmitted via tele-ultrasound from Brazil to Australia.

Methods: In this cross-sectional study, 15 normal singleton pregnant women between 20 and 26 weeks were selected. Fetal CNS structures were obtained by images and video clips. The exams were transmitted in real-time using a broadband internet and an inexpensive video streaming device. Four blinded examiners evaluated the quality of the exams using the Likert scale. We calculated the mean, standard deviation, mean difference, and p values were obtained from paired t tests.

Results: The quality of the original video clips was slightly better than that observed by the transmitted video clips; mean difference considering all observers = 0.23 points. In 47/60 comparisons (78.3%; 95% CI?=?66.4–86.9%) the quality of the video clips were judged to be the same. In 182/240 still images (75.8%; 95% CI?=?70.0–80.8%) the scores of transmitted image were considered the same as the original.

Conclusion: We demonstrated that long distance tele-ultrasound transmission of fetal CNS structures using an inexpensive video streaming device provided images of subjective good quality.  相似文献   
6.
7.
8.
9.
10.
Drug‐induced reactions are complications associated with high mortality and significant morbidity. Stevens–Johnson Syndrome (SJS) and toxic epidermal necrolysis (TEN) are examples of these conditions, which are characterized by skin and mucous lesions. Here, we report a case of a 9‐year‐old girl who presented with blisters associated with an extensive vesicular rash and multiple ulcerations on the lips and oral cavity. A drug‐induced hypersensitivity reaction to antibiotics was suspected, and a diagnosis of TEN was made. The patient was managed with withdrawal of the suspected causative agent, and the oral lesions were treated with low‐level laser therapy (LLLT) and oral hygiene. This case highlights that TEN requires interdisciplinary intervention with dental assistance and follow‐up to improve symptoms, nutrition, systemic condition, and quality of life.  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