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   449篇
  免费   95篇
  国内免费   6篇
耳鼻咽喉   5篇
儿科学   2篇
妇产科学   13篇
基础医学   56篇
口腔科学   5篇
临床医学   48篇
内科学   107篇
皮肤病学   4篇
神经病学   47篇
特种医学   12篇
外科学   56篇
综合类   8篇
预防医学   12篇
眼科学   15篇
药学   58篇
中国医学   1篇
肿瘤学   101篇
  2022年   6篇
  2021年   9篇
  2020年   12篇
  2019年   18篇
  2018年   24篇
  2017年   22篇
  2016年   24篇
  2015年   24篇
  2014年   12篇
  2013年   18篇
  2012年   23篇
  2011年   33篇
  2010年   19篇
  2009年   13篇
  2008年   21篇
  2007年   25篇
  2006年   18篇
  2005年   20篇
  2004年   12篇
  2003年   14篇
  2002年   15篇
  2001年   9篇
  2000年   13篇
  1999年   13篇
  1998年   7篇
  1997年   6篇
  1996年   7篇
  1995年   8篇
  1994年   7篇
  1993年   2篇
  1992年   3篇
  1991年   5篇
  1990年   5篇
  1989年   9篇
  1988年   2篇
  1987年   7篇
  1986年   3篇
  1985年   3篇
  1984年   5篇
  1981年   5篇
  1980年   3篇
  1979年   7篇
  1978年   2篇
  1977年   3篇
  1974年   3篇
  1973年   3篇
  1959年   2篇
  1958年   3篇
  1957年   4篇
  1956年   8篇
排序方式: 共有550条查询结果,搜索用时 0 毫秒
61.
Objective. Placental fetal vessel thrombosis or vasculitis and retroplacental hematoma have been associated with adverse neonatal outcomes. The activation of thrombin may contribute to the development of thrombosis and inflammation, and can be assessed through the measurement of thrombin-inhibitor complexes.

Methods. A nested case–control study was performed within a cohort of women with singleton gestations. Thrombin–antithrombin III (TAT) and Thrombin-Heparin co-factor II (T-HCII) concentrations were measured in first trimester maternal plasma. Cases were defined by retroplacental hematoma and/or fetal vessel thrombosis or vasculitis in the umbilical cord or chorionic plate. Outcomes were analysed with Mann–Whitney U and linear regression.

Results. Concentrations of both TAT (p = 0.013) and T-HCII (p = 0.001) from maternal plasma was significantly lower in cases than in controls.

Conclusions. The development of placental inflammatory and thrombotic lesions at term may be associated with lower concentrations of thrombin-inhibitor complexes earlier in the pregnancy.  相似文献   
62.
IntroductionThe roles of testosterone and orchiectomy on male bladder subjected to ischemic/reperfusion (I/R) injuries received little attention. To fill this gap, the present study intended to examine testosterone and orchiectomy effects on male rabbits subjected to I/R damages.AimTo elucidate the effects of testosterone and orchiectomy on contractile response, bladder morphology, interstitial fibrosis, and oxidative stress in male rabbit bladder subjected to I/R surgery.MethodsMale New Zealand rabbits were distributed into five groups as follows: Group 1 received sham surgical procedure. In group 2, I/R surgery was performed. In group 3, testosterone (100 μg/kg/day) was intramuscularly injected prior to I/R surgery. In group 4, orchiectomy was performed prior to I/R surgery. In group 5, orchiectomy was performed with subsequent testosterone administration, followed by I/R surgery. All the rabbits were euthanized 7 days after I/R. Comparative studies were analyzed to elucidate the effects of testosterone and orchiectomy on bladder dysfunction subjected to I/R injuries.Main Outcome MeasuresBladder contractile function was evaluated. Masson's trichrome staining and immunohistochemical studies were performed to evaluate bladder morphology and intramural nerve terminals. Western blotting was examined to investigate the expressions of fibrosis and oxidative stress markers.ResultsI/R surgery significantly decreased bladder contractility in response to various stimulations with and without testosterone treatment. I/R damages decreased bladder nerve density with and without testosterone. The expressions of fibrosis and oxidative stress‐related proteins were increased by I/R injuries with or without testosterone treatment. Testosterone depletion significantly decreased the expressions of transforming growth factor‐β and fibronectin expressions after I/R injury. Supraphysiological testosterone treatment after orchiectomy greatly increased the expressions of these fibrosis proteins; however, orchiectomy alone ameliorated I/R injuries.ConclusionsTestosterone treatment or orchiectomy affected I/R‐induced bladder damages in male rabbits. Orchiectomy decreased the level of fibrosis and oxidative stress markers and increased neurofilament densities. Supraphysiological exogenous testosterone administration after orchiectomy further exacerbated such detrimental effects of I/R.  相似文献   
63.
64.
65.
A large, well-encapsulated intraneural lipoma occurred within the sciatic nerve of a 34-year-old woman. In a review of the literature, significant differences were noted between the well-encapsulated and the diffusely infiltrative lipofibromatous hamartoma types of intraneural lipomas. The average age at the time of appearance of the well-encapsulated type is 45 years, with female predominance, while the infiltrative type arises in a younger age group (average age, eight years) with no sexual predominance. To avoid a recurrence, total excision is recommended in cases of the well-encapsulated type. Attempts to excise the diffusely infiltrative type are likely to fail.  相似文献   
66.
A human prostatic cell line JCA-1 has been shown to release into culture medium an activity that promotes the proliferation of murine fibroblast 3T3 cells. The presence of additional serum-free conditioned culture supernatant from JCA-1 cells accelerates the 3T3 growth rate as determined by cell counts, [3H]thymidine uptake into DNA and colony formation in soft agar gel. The growth activity was determined not to derive from culture medium components. Treatment of JCA-1 cells with RNA synthesis inhibitor actinomycin D abrogated the activity, indicating that protein synthesis is required for the presence of this activity from JCA-1 cells. The molecular mass of this prostatic cell derived growth factor (PRGF) was larger than 10,000 KDa, and its interaction with fibroblasts resulted in an approximate 27 percent increase in replicating cell cycle phases S and G2M with a reciprocal decrease of G1 cells. These data indicated a mechanism causing a more rapid entry of cells into replication. The interaction between prostatic cancer cells and related tissues and their relation to pathogenesis is reviewed.  相似文献   
67.
68.
Using the 2003 Kenya Demographic and Health Survey, we investigated the influence of individual- and community-level factors on accepting attitudes toward people living with HIV (PLHIV) using three outcomes: (1) willingness to care for an infected household member, (2) willingness to buy vegetables from an infected vendor, and (3) willingness to allow an infected female teacher to continue teaching. In multilevel logistic regression models, we found that individuals who expressed greater acceptance of PLHIV were more likely to be male, older, more educated, high AIDS knowledge, and exposed to mass media. At the community level, differences in accepting attitudes were associated with community AIDS knowledge, community education, and community AIDS experience, but not for region, or place of residence. The findings suggest the important role of community factors in determining social acceptance of PLHIV. Programmatic strategies aimed at increasing these accepting attitudes should consider both individual- and community-level factors.  相似文献   
69.
The present study investigated the efficacy of cognitive bibliotherapy in the treatment of depressive symptoms among Chinese individuals in Taiwan. Adults with depressive symptoms (N = 52, M age = 26.4) were randomly assigned to the treatment condition or the delayed treatment control condition. Participants were assessed at pretreatment, posttreatment, and 3-month follow-up. Results indicated that participants’ overall depression level lowered at posttreatment. Analyses were performed on the intention-to-treat basis. Multiple imputation inference procedure (Rubin in Multiple imputation for nonresponse in surveys, John Wiley & Sons, Inc., New York 1987) was adopted to estimate missing values and to draw inferences based on the imputed data. Results of the analyses indicated that the cognitive-affective symptoms of depression, rather than the somatic symptoms of depression, evidenced significant reduction as a result of cognitive bibliotherapy. Further reductions in cognitive-affective symptoms were observed at 3-month follow-up. Lastly, learned resourcefulness was found to be a mechanism through which bibliotherapy reduced depressive symptoms. The present study provides preliminary evidence that cognitive bibliotherapy may be a promising treatment option for Chinese individuals with depressive symptoms. In the meantime, participants’ qualitative feedback may provide important direction for cross-cultural adaptation of cognitive bibliotherapy. Applied implications and cultural issues are discussed.  相似文献   
70.
Establishment of new human prostatic cancer cell line (JCA-1)   总被引:2,自引:0,他引:2  
The establishment of a new human prostatic cancer cell line is described. This cell line was derived from a poorly to moderately differentiated prostatic adenocarcinoma. It has been maintained in tissue culture for fourteen months and has been passed fifty-two times. This cell line has an ability to form colonies in soft agar suspension cultures, and also is transplantable to nude mice. Tumors grown in nude mice revealed a poorly differentiated adenocarcinoma with positive PSA staining. Acid phosphatase activity was detected in freeze-thawed cells by enzymatic assay. A karyotype analysis demonstrated aneuploidy with a model chromosomal number of 69 and six marker chromosomes.  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