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   995篇
  免费   63篇
  国内免费   3篇
耳鼻咽喉   13篇
儿科学   45篇
妇产科学   11篇
基础医学   132篇
口腔科学   19篇
临床医学   94篇
内科学   145篇
皮肤病学   11篇
神经病学   93篇
特种医学   15篇
外科学   261篇
综合类   9篇
一般理论   2篇
预防医学   74篇
眼科学   21篇
药学   55篇
肿瘤学   61篇
  2021年   9篇
  2020年   11篇
  2019年   18篇
  2018年   18篇
  2017年   13篇
  2016年   9篇
  2015年   14篇
  2014年   35篇
  2013年   27篇
  2012年   71篇
  2011年   49篇
  2010年   28篇
  2009年   27篇
  2008年   41篇
  2007年   68篇
  2006年   80篇
  2005年   69篇
  2004年   54篇
  2003年   56篇
  2002年   45篇
  2001年   30篇
  2000年   30篇
  1999年   20篇
  1998年   12篇
  1996年   12篇
  1995年   13篇
  1994年   7篇
  1993年   4篇
  1992年   14篇
  1991年   16篇
  1990年   19篇
  1989年   14篇
  1988年   10篇
  1987年   8篇
  1986年   6篇
  1985年   16篇
  1984年   9篇
  1983年   7篇
  1980年   3篇
  1979年   6篇
  1977年   5篇
  1976年   3篇
  1975年   3篇
  1974年   6篇
  1973年   3篇
  1972年   3篇
  1970年   4篇
  1968年   4篇
  1967年   3篇
  1966年   3篇
排序方式: 共有1061条查询结果,搜索用时 10 毫秒
41.
Body mass index (BMI) > 35‐40 kg/m2 is often a contraindication, while Roux‐en‐Y gastric bypass (RYGB) is performed to enable kidney transplantation. This single‐center retrospective study evaluated pre‐ and post‐transplant outcomes of 31 morbidly obese patients with end‐stage renal disease having RYGB before kidney transplantation between July 2009 and June 2014. Fourteen RYGB patients were subsequently transplanted. Nineteen recipients not having GB with a BMI ≥ 36 kg/m2 at transplantation were used as historical controls. Mean BMI (±SE) before RYGB was 43.5 ± 0.7 kg/m2 (range: 35.4‐50.5 kg/m2); 87.1% (27/31) achieved a BMI < 35 kg/m2. The percentage having improved diabetes/hypertension control was 29.0% (9/31); 25.8% (8/31) had complications (mostly minor) after RYGB. Among transplanted patients, blacks/Hispanics comprised 78.6% (11/14) and 84.2% (16/19) of RYGB and controls; 57.1% (8/14) and 63.2% (12/19) had a (mostly long‐standing) pretransplant history of diabetes. While biopsy‐proven acute rejection (BPAR) occurred significantly higher among RYGB vs control patients (6/14 vs 3/19, = .03), patients developing T‐cell BPAR were also significantly more likely to have a tacrolimus (TAC) trough level < 4.0 ng/mL within 3 weeks of T‐cell BPAR (= .0007). In Cox's model, the impact of having a TAC level < 4.0 ng/mg remained significant (= .007) while the effect of RYGB was no longer significant (= .13). Infections, graft, and patient survival were not significantly different. Despite obvious effectiveness in achieving weight loss, RYGB will need more careful post‐transplant monitoring given the observed higher BPAR rate.  相似文献   
42.
43.
44.
Clinical trials are probably the most informative experiments to help an understanding of multiple sclerosis (MS) biology. Recent successes with CD20‐depleting antibodies have focused attention towards B cell subsets as important mediators in MS. The trial of tabalumab (NTC00882999), which inhibits B cell activation factor (BAFF), is reported and reviewed and this trial is contrasted with the trial on the inhibition of a proliferation‐inducing ligand (APRIL) and BAFF using atacicept (NCT00642902). Both tabalumab and atacicept induce depletion of mature B cells and inhibit antibody formation, but they fail to deplete memory B cells and do not inhibit relapsing MS. Atacicept is reported to augment memory B cell responses and may precipitate relapse, suggesting the importance of APRIL. However, BAFF inhibition can enhance peripheral blood memory B cell responses, which was not associated with augmented relapse. Although other interpretations are possible, these data further support the hypothesis that memory B cells may be of central importance in relapsing MS, as they are the major CD20+ B cell subset expressing APRIL receptors. They also suggest that quantitative and/or qualitative differences in B cell responses or other factors, such as an immune‐regulatory effect associated with APRIL, may be important in determining whether MS reactivates following neutralization of peripheral B cell maturation and survival factors.  相似文献   
45.
46.
Aim: To examine the relevance of physical activity intensity when assessing the relationship between activity and psychological health in 9–10-year-old children.
Methods: Activity was assessed by accelerometry in 57 boys (n = 23) and girls (n = 34). Total activity and time spent in very light (≤1.9 METs) through to vigorous activity (≥6 METs) were recorded. Psychological health inventories to assess anxiety, depression and aspects of self-worth were completed.
Results: Time accumulated in very light activity had positive correlations with anxiety and depression (r > 0.30, p < 0.05) and negative correlations with aspects of physical self-worth (r > −0.29, p < 0.05). Time accumulated in vigorous activity had negative correlations with anxiety and behavioural conduct (r > −0.30, p < 0.05) and positive correlation with aspects of physical self-worth (r > 0.28, p < 0.05). Children spending over 4 h in very light intensity activity had more negative psychological profiles than children spending under 4 h at this intensity.
Conclusion: Aspects of psychological health were negatively correlated with very light intensity activity and positively correlated with vigorous intensity activity. Further research should investigate whether reducing time spent in very light intensity activity and increasing time spent in vigorous intensity activity improves psychological health in children.  相似文献   
47.
BACKGROUND: Early environment is a major determinant of long-term mental health, evidenced by the relationship between early-life neglect or abuse and chronically increased vulnerability to developmental psychopathology, including major depressive disorder (MDD). Animal studies can increase understanding of environmentally mediated causal risk processes. We describe how daily deprivation of biological parenting in primate infants disrupts development of homeostatic and reward systems central to MDD. METHODS: Nine breeding pairs of marmoset monkeys provided control twins (CON) and early-deprived twins (ED); the latter were socially isolated for 30-120 min/day on days 2-28. During the first year of life, basal urinary norepinephrine (NE) titers and cardiophysiologic activity were measured. At the end of year 1 (adolescence), automated neuropsychologic tests were conducted to measure responsiveness to changes in stimulus-reward association (simple/reversed visual discrimination learning) and to reward per se (progressive ratio [PR] reinforcement schedule). RESULTS: The ED monkeys exhibited increased basal urinary NE titers and increased systolic blood pressure relative to CON siblings. The ED monkeys required more sessions to reinstate stimulus-oriented behavior following reversal, suggesting increased vulnerability to perceived loss of environmental control; ED monkeys also performed less PR operant responses, indicating that reward was less of an incentive and that they were mildly anhedonic relative to CON. CONCLUSIONS: In marmoset monkeys, neglect-like manipulation of ED leads to chronic changes in homeostatic systems, similar to those in children and adolescents exposed to early-life adversity and in MDD, and to responses to environmental stimuli similar to those that characterize MDD.  相似文献   
48.
Tppp3, a member of the Tubulin polymerization‐promoting protein family, is an intrinsically unstructured protein that induces tubulin polymerization. We show that Tppp3 is a distinct marker in the developing musculoskeletal system. In tendons, Tppp3 is expressed in cells at the circumference of the developing tendons, likely the progenitors of connective tissues that surround tendons: the tendon sheath, epitenon, and paratenon. These tissues form an elastic sleeve around tendons and provide lubrication to minimize friction between tendons and surrounding tissues. Tppp3 is the first molecular marker of the tendon sheath, opening the door for direct examination of these tissues. Tppp3 is also expressed in forming synovial joints. The onset of Tppp3 expression in joints coincides with cavitation, representing a molecular marker that can be used to indicate this stage in joint transition in joint differentiation. In late embryonic stages, Tppp3 expression highlights other demarcation lines that surround differentiating tissues in the forelimb. Developmental Dynamics 238:685–692, 2009. © 2009 Wiley‐Liss, Inc.  相似文献   
49.
During neuroinflammation in multiple sclerosis (MS) fibrinogen, not normally present in the brain or spinal cord, enters the central nervous system through a compromised blood–brain barrier. Fibrin deposited on axons is ineffectively removed by tissue plasminogen activator (tPA), a key contributory factor being the upregulation of plasminogen activator inhibitor-1 (PAI-1). Aims: This study investigated the role of PAI-1 during experimental neuroinflammatory disease. Methods: Chronic relapsing experimental allergic encephalomyelitis (CREAE), a model of MS, was induced with spinal cord homogenate in PAI-1 knockout (PAI-1−/−) and wild type (WT) mice, backcrossed onto the Biozzi background. Results: Disease incidence and clinical severity were reduced in PAI-1−/− mice, with animals developing clinical signs significantly later than WTs. Clinical relapses were absent in PAI-1−/− mice and the subsequent reduction in neuroinflammation was coupled with a higher capacity for fibrinolysis in spinal cord samples from PAI-1−/− mice, in association with increased tPA activity. Axonal damage was less apparent in PAI-1−/− mice than in WTs, implicating fibrin in both inflammatory and degenerative events during CREAE. Conclusions: PAI-1 is a potential target for therapy in neuroinflammatory degenerative diseases, allowing effective fibrin removal and potentially reducing relapse rate and axonal damage.  相似文献   
50.
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