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   23969篇
  免费   1972篇
  国内免费   67篇
耳鼻咽喉   343篇
儿科学   716篇
妇产科学   600篇
基础医学   2989篇
口腔科学   464篇
临床医学   2640篇
内科学   4919篇
皮肤病学   376篇
神经病学   2568篇
特种医学   917篇
外科学   3308篇
综合类   461篇
一般理论   11篇
预防医学   2091篇
眼科学   475篇
药学   1708篇
中国医学   27篇
肿瘤学   1395篇
  2023年   123篇
  2022年   246篇
  2021年   532篇
  2020年   322篇
  2019年   484篇
  2018年   569篇
  2017年   418篇
  2016年   511篇
  2015年   582篇
  2014年   770篇
  2013年   967篇
  2012年   1543篇
  2011年   1539篇
  2010年   867篇
  2009年   705篇
  2008年   1346篇
  2007年   1306篇
  2006年   1251篇
  2005年   1186篇
  2004年   1014篇
  2003年   981篇
  2002年   874篇
  2001年   545篇
  2000年   544篇
  1999年   528篇
  1998年   233篇
  1997年   233篇
  1996年   190篇
  1995年   165篇
  1994年   157篇
  1993年   134篇
  1992年   309篇
  1991年   335篇
  1990年   355篇
  1989年   312篇
  1988年   277篇
  1987年   290篇
  1986年   258篇
  1985年   310篇
  1984年   240篇
  1983年   163篇
  1982年   134篇
  1981年   116篇
  1980年   129篇
  1979年   186篇
  1978年   152篇
  1975年   113篇
  1974年   141篇
  1973年   127篇
  1972年   124篇
排序方式: 共有10000条查询结果,搜索用时 760 毫秒
1.
2.
3.
4.
5.
Purpose:This study assessed the regeneration potential of mesenchymal stem cells (MSC) from adipose tissue associated with platelet-rich plasma (PRP) in bone regeneration.Methods:Thirty Wistar rats (Rattus norvegicus albinos) were divided into five groups (according to the grafting material and time to euthanasia): (1) autograft - 14 days (control), (2) autograft - 28 days (control), (3) MSC + PRP - 14 days, (4) MSC + PRP + papaverine - 14 days and (5) MSC + PRP + papaverine - 28 days. After euthanasia, the graft was removed and histological slides were prepared. They were assessed by a blinded pathologist using a previously published histological scale as parameter.Results:There was some degree of neoformed bone trabeculae (NBT) in 93.3% of the samples, as well as osteoblastic activity (OA). The autograft groups (14 and 28 days) had higher levels in the formation of bone trabeculae. Nonparametric data were analyzed using the Wilcoxon-Mann-Whitney test and proved not to be statistically significant at p < 0.05.Conclusions:Experimental parietal bone reconstruction, combining MSC, PRP and papaverine presented regeneration in all groups with no significant difference among them.Key words: Bone Regeneration, Platelet-Rich Plasma, Tissue Engineering, Rats  相似文献   
6.
Determining aortic stenosis (AS) severity is clinically important. Calculating aortic valve (AV) area by means of the continuity equation assumes a circular left ventricular outflow tract (LVOT). The full impact of this assumption in calculating AV area is unknown. Predictors of noncircular LVOT shape in patients with AS are undefined.In 109 adult patients with AS who underwent multiplanar transesophageal echocardiography, we calculated AV area by means of the standard continuity method and by a modified method involving planimetric LVOT area.We found 54 circular, 37 horizontal-oval, 8 vertical-oval, and 10 irregular LVOTs. Area derived by direct planimetry correlated better with the modified than the standard continuity method (r=0.89 vs r=0.85; both P=0.0001). Valve areas of patients with mild, moderate, or severe AS by planimetry were more often mischaracterized with use of the standard than modified method (29 vs 18; P <0.0001). Horizontal-oval AV area derived by planimetry (1.28 ± 0.55 cm2) was underestimated by the standard method (1.05 ± 0.47 cm2; P=0.001), but not by the modified method. Congenital AV morphology and low cardiac index were the only multivariate predictors of horizontal-oval shape. Low cardiac index was the only predictor of noncircular shape.More than half our patients with AS had noncircular LVOTs. Using the modified method reduces mischaracterizations of AS severity. Congenital AV morphology and low cardiac index predict horizontal-oval or noncircular shape. These data suggest the value of direct LVOT measurement to calculate AS severity in patients who have congenital AV or a low cardiac index.  相似文献   
7.

Background

A history of childhood maltreatment and psychopathology are common in adults with obesity.

Objectives

To report childhood maltreatment and to evaluate associations between severity and type of childhood maltreatment and lifetime history of psychopathology among adults with severe obesity awaiting bariatric surgery.

Setting

Four clinical centers of the Longitudinal Assessment of Bariatric Surgery Research Consortium.

Methods

The Childhood Trauma Questionnaire, which assesses presence/severity (i.e., none, mild, moderate, severe) of physical abuse, mental abuse, physical neglect, mental neglect, and sexual abuse, was completed by 302 female and 66 male bariatric surgery patients. Presurgery lifetime history of psychopathology and suicidal ideation/behavior were assessed with the Structured Clinical Interview for DSM-IV and the Suicidal Behavioral Questionnaire-Revised, respectively. Presurgery lifetime history of antidepressant use was self-reported.

Results

Two thirds (66.6%) of females and 47.0% of males reported at least 1 form of childhood trauma; 42.4% and 24.2%, respectively, at greater than or equal to moderate severity. Among women, presence/greater severity of childhood mental or physical abuse or neglect was associated with a higher risk of history of psychopathology (i.e., major depressive disorder, posttraumatic stress disorder, other anxiety disorder, alcohol use disorder, binge eating disorder), suicidal ideation/behavior and antidepressant use (P for all ≤ .02). These associations were independent of age, race, education, body mass index, and childhood sexual abuse. Childhood sexual abuse was independently associated with a history of suicidal ideation/behavior and antidepressant use only (P for both ≤ .05). Statistical power was limited to evaluate these associations among men.

Conclusion

Among women with obesity, presence/severity of childhood trauma was positively associated with relatively common psychiatric disorders.  相似文献   
8.
9.
10.
2‐deoxy D‐glucose (2DG) was tested for efficacy in treating alopecia areata using the C3H/HeJ skin graft model. 2DG has proven to be efficacious in treatment of various mouse models of autoimmunity with minimal serious side effects noted. This agent has been shown to normalize abnormally activated T‐cell populations while also preventing cell surface expression of NKG2D; key factors defining alopecia areata disease progression. Daily oral ingestion of 2DG via drinking water to mice with patchy or diffuse alopecia areata for 16 weeks failed to prevent expansion of alopecia or cause regrowth of hair in treated mice. Histologically, there were no differences between treated and control groups. These results indicate that, while 2DG is effective for some autoimmune diseases, it was not efficacious for the cell‐mediated autoimmune mouse disease, alopecia areata.  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