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   64139篇
  免费   4141篇
  国内免费   236篇
耳鼻咽喉   620篇
儿科学   1746篇
妇产科学   1429篇
基础医学   9305篇
口腔科学   2825篇
临床医学   6748篇
内科学   12846篇
皮肤病学   1281篇
神经病学   6025篇
特种医学   1462篇
外国民族医学   5篇
外科学   6283篇
综合类   393篇
一般理论   34篇
预防医学   7368篇
眼科学   1129篇
药学   4585篇
  1篇
中国医学   361篇
肿瘤学   4070篇
  2023年   465篇
  2022年   442篇
  2021年   1990篇
  2020年   1312篇
  2019年   1797篇
  2018年   2200篇
  2017年   1484篇
  2016年   1697篇
  2015年   2016篇
  2014年   2572篇
  2013年   3433篇
  2012年   4967篇
  2011年   5352篇
  2010年   2722篇
  2009年   2358篇
  2008年   4035篇
  2007年   4194篇
  2006年   3771篇
  2005年   3486篇
  2004年   3166篇
  2003年   2999篇
  2002年   2647篇
  2001年   899篇
  2000年   854篇
  1999年   771篇
  1998年   508篇
  1997年   386篇
  1996年   340篇
  1995年   287篇
  1994年   290篇
  1993年   270篇
  1992年   412篇
  1991年   389篇
  1990年   370篇
  1989年   382篇
  1988年   284篇
  1987年   247篇
  1986年   251篇
  1985年   219篇
  1984年   216篇
  1983年   171篇
  1982年   154篇
  1981年   131篇
  1980年   121篇
  1979年   164篇
  1978年   93篇
  1976年   90篇
  1974年   103篇
  1970年   87篇
  1969年   88篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Evidence continues to grow on potential environmental health hazards associated with engineered nanomaterials (ENMs). While the geno- and cytotoxic effects of ENMs have been investigated, their potential to target the epigenome remains largely unknown. The aim of this study is two-fold: 1) determining whether or not industry relevant ENMs can affect the epigenome in vivo and 2) validating a recently developed in vitro epigenetic screening platform for inhaled ENMs. Laser printer-emitted engineered nanoparticles (PEPs) released from nano-enabled toners during consumer use and copper oxide (CuO) were chosen since these particles induced significant epigenetic changes in a recent in vitro companion study. In this study, the epigenetic alterations in lung tissue, alveolar macrophages and peripheral blood from intratracheally instilled mice were evaluated. The methylation of global DNA and transposable elements (TEs), the expression of the DNA methylation machinery and TEs, in addition to general toxicological effects in the lung were assessed. CuO exhibited higher cell-damaging potential to the lung, while PEPs showed a greater ability to target the epigenome. Alterations in the methylation status of global DNA and TEs, and expression of TEs and DNA machinery in mouse lung were observed after exposure to CuO and PEPs. Additionally, epigenetic changes were detected in the peripheral blood after PEPs exposure. Altogether, CuO and PEPs can induce epigenetic alterations in a mouse experimental model, which in turn confirms that the recently developed in vitro epigenetic platform using macrophage and epithelial cell lines can be successfully utilized in the epigenetic screening of ENMs.  相似文献   
12.
Archives of Gynecology and Obstetrics - The objective of this study was to determine if high-dose antibiotic prophylaxis with cefazolin decreases the risk of surgical site infection (SSI) after a...  相似文献   
13.
14.
15.
16.
17.
18.
19.
20.

Objectives

To determine the incidence of incisional hernia (IH) in the extraction incision (EI) in colorectal resection for cancer. To analyze whether the location of the incision has any relationship with the incidence of hernias and whether mesh could be useful for prevention in high-risk patients.

Methods

Retrospective review of the colon and rectal surgery database from January 2015 to December 2016. Data were classified into 2 groups, transverse (TI) and midline incision (MI), and the latter was divided into 2 subgroups (mesh [MIM] and suture [MIS]). Patients were classified using the HERNIAscore. Hernias were diagnosed by clinical and/or CT examination.

Results

A total of 182 out of 210 surgical patients were included. After a median follow-up of 13.0 months, 39 IH (21.9%) were detected, 23 of which (13.4%) were in the EI; their frequency was lower in the TI group (3.4%) and in the MIM group (5.9%) than in the MIS group (29.5%; p = 0.007). The probability of developing IH in the MIS group showed an OR = 11.7 (95%CI: 3.3-42.0) compared to the TI group and 4.3 (IC 95%: 1.1-16.3) versus the MIM group.

Conclusions

The location of the incision is relevant to avoid incisional hernias. Transverse incisions should be used as the first option. When a midline incision is needed, a prophylactic mesh could be considered in high risk patients because it is safe and associated with low morbidity.  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