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   296314篇
  免费   14981篇
  国内免费   648篇
耳鼻咽喉   3908篇
儿科学   8834篇
妇产科学   6325篇
基础医学   42035篇
口腔科学   7892篇
临床医学   23370篇
内科学   66494篇
皮肤病学   7586篇
神经病学   26617篇
特种医学   9090篇
外国民族医学   106篇
外科学   36835篇
综合类   1356篇
一般理论   84篇
预防医学   27169篇
眼科学   5655篇
药学   20810篇
中国医学   910篇
肿瘤学   16867篇
  2023年   1605篇
  2022年   1586篇
  2021年   5293篇
  2020年   3020篇
  2019年   5442篇
  2018年   10644篇
  2017年   6873篇
  2016年   6348篇
  2015年   7198篇
  2014年   8097篇
  2013年   12500篇
  2012年   20362篇
  2011年   20287篇
  2010年   10693篇
  2009年   8379篇
  2008年   17304篇
  2007年   18309篇
  2006年   17108篇
  2005年   16840篇
  2004年   15686篇
  2003年   14398篇
  2002年   13562篇
  2001年   7065篇
  2000年   7210篇
  1999年   6364篇
  1998年   1425篇
  1997年   1128篇
  1996年   1059篇
  1995年   964篇
  1992年   3624篇
  1991年   3220篇
  1990年   3066篇
  1989年   2806篇
  1988年   2599篇
  1987年   2466篇
  1986年   2311篇
  1985年   2109篇
  1984年   1593篇
  1983年   1334篇
  1979年   1362篇
  1978年   975篇
  1977年   909篇
  1975年   918篇
  1974年   1107篇
  1973年   1117篇
  1972年   1044篇
  1971年   1023篇
  1970年   946篇
  1969年   982篇
  1968年   880篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.

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   
62.
Food-grade titanium dioxide (E171) is widely used as a food additive, and it is known that after oral consumption, E171 is translocated into the bloodstream reaching the highest titanium level at 6 h. E171 is accumulated in some organs triggering toxicity, but the effects on the blood parameters after oral consumption have been less studied. Recently, evidence shows that oral exposure to E171 induces behavioral signs of anxiety and depression. The relation between blood alterations and psychiatric disorders has been previously demonstrated. However, the oral exposure to E171 effects on alterations in blood parameters and effects linked to alterations in animal behavior has not been explored. In this short communication, we aimed to investigate the effects of E171 on specific blood parameters (hematocrit, hemoglobin, number of erythrocytes, and leukocytes) and anxiety and compulsive-like behavior in males and females orally exposed to ~5 mg/kg for 4 weeks. The results showed that E171 decreased hematocrit and hemoglobin in male but not in female mice while leukocyte and erythrocyte count remained unaltered. Oral consumption of E171 decreased the levels of anxiety-like behavior in females but not in male mice, while compulsive-like behavior was increased in both male and female mice.  相似文献   
63.
64.
65.
66.
Magnetic resonance elastography aims to non-invasively and remotely characterize the mechanical properties of living tissues. To quantitatively and regionally map the shear viscoelastic moduli in vivo, the technique must achieve proper mechanical excitation throughout the targeted tissues. Although it is straightforward, ante manibus, in close organs such as the liver or the breast, which practitioners clinically palpate already, it is somewhat fortunately highly challenging to trick the natural protective barriers of remote organs such as the brain. So far, mechanical waves have been induced in the latter by shaking the surrounding cranial bones. Here, the skull was circumvented by guiding pressure waves inside the subject's buccal cavity so mechanical waves could propagate from within through the brainstem up to the brain. Repeatable, reproducible and robust displacement fields were recorded in phantoms and in vivo by magnetic resonance elastography with guided pressure waves such that quantitative mechanical outcomes were extracted in the human brain.  相似文献   
67.
Background: Most theoretical models of self-determination suggest that both environmental and personal factors influence the development of self-determination. The design and implementation of interventions must be conducted with foreknowledge of such mediating and moderating factors if the intervention is to be successful.

Methods: The purpose of this study was to examine the degree to which several personal factors and school characteristics affect and explain students’ self-determination. A total of 232 students with intellectual disability from Spain participated. Their self-determination level was assessed by the ARC-INICO Scale.

Results: Students with moderate levels of intellectual disability obtained significantly lower scores on self-determination than their peers with mild intellectual disability. There were significant differences in relation to the level of support needs and their experience with transition programs. The level of support needs was a significant predictor.

Conclusion: These findings contribute to current research in this field and practical implications were discussed.  相似文献   

68.
Journal of Digital Imaging - Vertebral Compression Fracture (VCF) occurs when the vertebral body partially collapses under the action of compressive forces. Non-traumatic VCFs can be secondary to...  相似文献   
69.
70.
European Journal of Clinical Microbiology & Infectious Diseases - We compared the performance of an in-house-developed flow cytometry assay for intracellular cytokine staining (FC-ICS) and a...  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