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   28440篇
  免费   1555篇
  国内免费   105篇
耳鼻咽喉   446篇
儿科学   576篇
妇产科学   377篇
基础医学   3988篇
口腔科学   728篇
临床医学   1934篇
内科学   6951篇
皮肤病学   733篇
神经病学   1985篇
特种医学   1137篇
外国民族医学   1篇
外科学   4551篇
综合类   127篇
一般理论   2篇
预防医学   833篇
眼科学   413篇
药学   2172篇
中国医学   87篇
肿瘤学   3059篇
  2021年   453篇
  2020年   313篇
  2019年   381篇
  2018年   498篇
  2017年   387篇
  2016年   485篇
  2015年   470篇
  2014年   710篇
  2013年   799篇
  2012年   1304篇
  2011年   1433篇
  2010年   804篇
  2009年   755篇
  2008年   1275篇
  2007年   1448篇
  2006年   1357篇
  2005年   1426篇
  2004年   1366篇
  2003年   1183篇
  2002年   1149篇
  2001年   1038篇
  2000年   968篇
  1999年   915篇
  1998年   315篇
  1997年   217篇
  1996年   224篇
  1995年   213篇
  1994年   175篇
  1993年   202篇
  1992年   634篇
  1991年   561篇
  1990年   537篇
  1989年   535篇
  1988年   518篇
  1987年   487篇
  1986年   460篇
  1985年   430篇
  1984年   318篇
  1983年   260篇
  1982年   164篇
  1979年   248篇
  1978年   163篇
  1977年   189篇
  1975年   159篇
  1973年   180篇
  1972年   189篇
  1971年   190篇
  1970年   172篇
  1969年   186篇
  1968年   171篇
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
1.
2.
Background: We developed a surgical knee rest (SKR) that can be used to decrease the stress placed on the lower half of the body when surgeons work in the standing position. We tested the effectiveness of this device in the context of laparoscopic surgery.

Material and methods: Five healthy, right-handed male surgeons participated, and we recorded surface electromyography (sEMG) signals from the two heads of the left and right gastrocnemius (Gc) muscles during laparoscopic resections of colorectal cancer. The outcome variable was the percentage of maximum Gc muscle effort generated, reported as percent maximal isometric voluntary contraction (%MVC), and this variable was compared between surgeries performed with and without use of the SKR. Assessment covered the first 100?min of surgery, subdivided into two 50-min periods.

Results: Mean %MVC of the left Gc muscle for the full 100-min test period was significantly decreased when the SKR was used (p?=?.027, vs. SKR not used). Notably, mean %MVC of both Gc muscles was significantly decreased during the first 50?min of surgery (p?=?.008 and p?=?.0046).

Conclusion: The SKR is useful for decreasing physical stress incurred by laparoscopic surgeons when working in the standing position.  相似文献   

3.
We report a case of kerion celsi due to Trichophyton tonsurans. An 18‐year‐old male student judo practitioner had alopecic patches, black dots and subcutaneous abscesses on the right temporal region. The damaged hair represented endothrix infection with T. tonsurans, as assessed by mycological examinations. He was treated with oral itraconazole without any therapeutic effect, followed by terbinafine with good effect. A skin biopsy showed neutrophil, lymphocyte and histiocyte infiltration into the dermis and subcutaneous tissue with abscesses around a number of dilated hair follicles. Immunostaining showed that the expression level of human β‐defensin 2 (HBD‐2) was decreased in the epidermis of the alopecic and adjacent skin. Because interleukin (IL)‐17A generally induces HBD‐2 production by epidermal keratinocytes, we also immunohistochemically investigated IL‐17A expression. Unexpectedly, many IL‐17A‐bearing cells were found around destructed hair follicles, indicating that IL‐17A expression was not attenuated, but rather increased in the skin lesion. Our case suggests that IL‐17A‐upregulated antimicrobial peptide expression is disordered in kerion celsi, and severe inflammation with IL‐17A may cause tissue damage and resultant scar.  相似文献   
4.
5.
6.
The consumption of red meat has been recommended for individuals with reduced kidney function. However, red meat intake was recently suspected to increase cardiovascular disease (CVD) risk. We evaluated the association of red meat intake with CVD mortality risk in Japanese with/without reduced kidney function. Overall, 9112 participants of a Japanese national survey in 1980, aged ≥30 years, were followed for 29 years. Red meat intake was assessed using weighed dietary record. Cox proportional hazards models were used to estimate the hazard ratio (HR) of CVD mortality according to sex-specific tertiles of red meat intake. We also performed stratified analyses with/without reduced kidney function defined as estimated glomerular filtration rate less than 60 mL/min/1.73 m2. Red meat intake was not associated with CVD mortality risk in men and women. In stratified analyses, the HR of the highest compared with the lowest tertile of red meat intake was lower only in women with reduced kidney function (0.67, 95% confidence interval 0.46–0.98). In conclusion, there were no clear associations between red meat intake and CVD mortality risk in Japanese population; however, a higher intake of red meat was associated with lower risk of future CVD mortality in women with reduced kidney function.  相似文献   
7.
8.
9.
Purpose:It has been reported previously that intravenously administered gadolinium-based contrast agent (GBCA) leaks into the subarachnoid space around the cortical veins at 4 h after injection in all old people over 37 years, but not in younger people up to 37 years of age in 3D-real IR images. The purpose of this study was to investigate whether there was a strict threshold of 37 years of age for the leakage of the GBCA into the subarachnoid space.Methods:The subjects included 190 patients, that were scanned for 3D-real IR images at 4 hours after intravenous injection of GBCA as a diagnostic test for endolymphatic hydrops. The patient’s age ranged from 14 to 81 years. Two experienced neuroradiologists evaluated the images to determine whether the GBCA leakage around the cortical veins was positive or negative. Any discrepancies between the two observers were discussed and a consensus was obtained.A Mann–Whitney U test and receiver operating characteristic (ROC) curve analysis were used to compare the positive and the negative group and to set the age cut-off value for the prediction of GBCA leakage.Results:The GBCA leakage around the cortical veins was negative in 35 patients and positive in 155 patients. The average age was 33 ± 11 years in the negative group, and 55 ± 12 years in the positive group (P < 0.01). In the ROC analysis for the age and leakage of the GBCA, an area under the curve was 0.905 and the cut-off age was 37.317 years (sensitivity of 0.942 and specificity of 0.771).Conclusion:Intravenously administered GBCA leaks into the subarachnoid space around the cortical veins in most patients over 37 years of age. However, it should be noted that it can be found occasionally in patients under 37 years of age.  相似文献   
10.
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