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   1225篇
  免费   82篇
  国内免费   61篇
耳鼻咽喉   11篇
儿科学   45篇
妇产科学   21篇
基础医学   151篇
口腔科学   37篇
临床医学   185篇
内科学   156篇
皮肤病学   12篇
神经病学   109篇
特种医学   134篇
外科学   183篇
综合类   45篇
一般理论   2篇
预防医学   112篇
眼科学   21篇
药学   78篇
中国医学   2篇
肿瘤学   64篇
  2021年   23篇
  2020年   7篇
  2018年   23篇
  2017年   12篇
  2016年   13篇
  2015年   17篇
  2014年   17篇
  2013年   52篇
  2012年   38篇
  2011年   43篇
  2010年   40篇
  2009年   36篇
  2008年   30篇
  2007年   81篇
  2006年   33篇
  2005年   54篇
  2004年   25篇
  2003年   27篇
  2002年   28篇
  2001年   26篇
  2000年   37篇
  1999年   50篇
  1998年   38篇
  1997年   46篇
  1996年   29篇
  1995年   28篇
  1994年   22篇
  1993年   31篇
  1992年   28篇
  1991年   25篇
  1990年   24篇
  1989年   40篇
  1988年   36篇
  1987年   24篇
  1986年   24篇
  1985年   23篇
  1984年   28篇
  1983年   26篇
  1982年   8篇
  1981年   14篇
  1980年   16篇
  1979年   14篇
  1978年   11篇
  1977年   7篇
  1975年   7篇
  1974年   8篇
  1973年   7篇
  1972年   9篇
  1971年   7篇
  1966年   8篇
排序方式: 共有1368条查询结果,搜索用时 0 毫秒
11.
Understanding how normal and immortalized bronchial epithelial cells respond to modulators of gap junctional communication will increase our understanding of the process of tumor promotion. In the present study we compared to effects of retinoic acid (RA) and 12-O-tetradecanoylphorbol-13-acetate (TPA) on the rate of fluorescent dye transfer via gap junctions in primary human tracheo-bronchial epithelial cells (TBE) and SV40 large T-antigen immortalized, non-tumorigenic bronchial epithelial cells (BEAS-2B). RA in the physiological range (0.001-1 microM) inhibited cell proliferation (DNA synthesis, mitotic index) more in primary TBE cells than BEAS-2B cells. Also in RA-treated cells, decreased cell proliferation was coupled to decreased gap junctional communication (GJC) in TBE but not in BEAS-2B cells. TPA strongly suppressed GJC and proliferation in primary TBE cells, whereas BEAS-2B exhibited increased GJC and retained a significant fraction of cells undergoing DNA synthesis. Our studies show that an uncoupling of GJC and cell proliferation is associated with a differential response to the growth inhibitory effects of RA and phorbol esters in immortalized compared to primary human bronchial epithelial cells.  相似文献   
12.
Survival of satellite cells in whole muscle transplants   总被引:4,自引:0,他引:4  
The ability of satellite cells to survive the ischemic conditions at the core of orthotopically free grafted rat extensor digitorum longus muscles was examined. Cell cultures of isolated core and peripheral regions of whole muscle grafts maintained in vivo for more than 24 hours indicated that no viable cells were present in the core, whereas the number of cells from the peripheral region was greatly increased. Muscles were examined with the electron microscope to determine the fate of satellite cells of the core at various times after transplantation. The population of satellite cells in the core was reduced beginning at 18 hours and had virtually disappeared by 24-28 hours. This reduction did not appear to be the result of satellite cell death. Although there was abundant morphological evidence that myonuclei as well as myofiber cytoplasmic organelles were degenerating, there was little indication of satellite cell death in situ any time period studied. These studies suggest that satellite cells cannot survive, but migrate from the ischemic core to more peripheral regions of whole muscle transplants. In addition, they suggest that migration is an important aspect of the regeneration response in the free graft system and permits the myogenic population to contribute en masse to the centripetal wave of regeneration from the time it is initiated at the muscle periphery.  相似文献   
13.
J. H. Saurat    L. Galoppin    CL. Ponvert  J. Paupe 《Allergy》1978,33(3):125-129
The leucocyte migration test (LMT) was performed on 20 patients with an intolerance to glafenin--a non-narcotic analgesic drug. LMT was found to be positive in 50% of the subjects with intolerance, a highly significant percentage as compared with the control groups. HSA-glafenin was found to be the most appropriate method for presenting the antigen, but glafenin and its hydroxylated metabolites were only found to induce a migration inhibition in the subjects intolerant to glafenin.  相似文献   
14.
Maternal and Child Health Journal - Alcohol use during pregnancy is a critical public health issue that results in several adverse outcomes for both mother and child. While the prevalence of and...  相似文献   
15.
Total ankle arthroplasty (TAA) is used as an alternative to ankle arthrodesis for adults with severe ankle arthritis. Numerous orthopedic centers have entered the healthcare market offering fast-tracked joint replacement protocols, meanwhile, TAA has been excluded from these joint centers, and is primarily performed in the inpatient setting. The purpose of this study is to examine short-term complications in the inpatient and outpatient settings following TAA using a systematic review and quantitative analysis. We considered all studies examining short-term complications following TAA performed in the inpatient versus outpatient setting occuring within 1 year of the index operation. We summarized data using a pooled relative risk and random effects model. A pooled sensitivity analysis was performed for studies with data on complication rates for inpatient or outpatient populations, which did not have a control group. The quality of included studies was assessed using the Cochrane risk of bias tool. Nine studies were included in the quantitative analysis, with 4 studies in the final meta-analysis. Subjects undergoing inpatient surgery experienced a 5-times higher risk of short-term complications compared to the outpatient group (risk ratio 5.27, 95% confidence interval 3.31, 8.42). Results did not change after sensitivity analysis (inpatient weighted mean complication rate: 9.62% vs outpatient weighted mean 5.02%, p value <.001). The overall level of evidence of included studies was level III, with a moderate to high risk of bias. Outpatient TAAs do not appear to pose excess complication risks compared to inpatient procedures, and may therefore be a reasonable addition to experienced centers that have established a fast-track outpatient total joint protocol.  相似文献   
16.
Archives of Sexual Behavior - Sexual minority men (SMM) remain disproportionately burdened by sexually transmitted infections. Although gay community involvement has been theorized to be protective...  相似文献   
17.
Natural killer activity in mice infected with Trypanosoma musculi.   总被引:2,自引:2,他引:2       下载免费PDF全文
Reproducing forms of Trypanosoma lewisi isolated from X-irradiated rats and adult forms from intact rats were not lysed by fresh mammalian sera. Treating parasites with trypsin or chymotrypsin, but not with neuraminidase, under conditions which did not impair viability rendered the parasites sensitive to lysis by rat, mouse, rabbit, and human sera. Serum from animal strains or humans genetically deficient in complement component C3, C5, or C6 did not lyse protease-treated parasites. The lytic factors in serum displayed the heat sensitivity and the Mg2+ requirement characteristic of the alternate complement pathway. Lysis was resolved into two phases, Mg2+-dependent binding of serum factors to parasites and subsequent C5-dependent, Mg2+-independent lysis. Allowing protease-treated parasites to readsorb host proteins did not block lysis by serum. Protease-treated parasites regenerated components which prevented complement-mediated lysis during 2 h in culture at 37 degrees C. This regeneration was inhibited by cycloheximide but not by tunicamycin. Ten major components were resolved in radioautographs of sodium dodecyl sulfate-polyacrylamide gels of extracts of radioiodinated intact cells. Protease treatment before radioiodination reduced the amount of radioactivity associated with these components disproportionately. Components with apparent molecular weights of 102,000, 88,000, and 47,000 were strongly labeled in intact cells, poorly labeled after enzyme treatment, and again labeled in cells that were cultured at 37 degrees C after enzyme treatment. Cycloheximide blocked the reappearance of these components on cultured cells. The presence of these three components was therefore correlated with resistance to complement-mediated lysis.  相似文献   
18.
The Wistar Diabetic Fatty rat (WDF fafa) is a congenic strain of the Wistar Kyoto rat. Studies using blood glucose reveal that only fatty male (not female) WDF rats spontaneously develop hyperglycemia when fed a stock diet. Blood glucose values have not provided consistent results for evaluation of glycemic status in fatty male WDF rats. Zucker fatty (fafa) rats, while sharing the fa gene and the development of hyperinsulinemia and hyperlipemia, do not spontaneously become hyperglycemic. In order to examine strain differences and the effects of age on long-term average glycemic status in WDF and Zucker rats, glycated hemoglobin (GHb) was analyzed. Glycated hemoglobin was measured in male lean and obese WDF and Zucker rats at 2, 3, 6, and 12 months of age. Nonfasted plasma glucose was measured in male lean and obese WDF rats at 2, 3, 6, and 12 months of age and in lean and obese Zucker rats at 3, 6, and 12 months of age. Plasma insulin was measured in lean and obese WDF and Zucker rats at 3, 6, and 12 months of age. Obese WDF rats had significantly elevated GHb compared to lean controls at 3, 6, and 12 months of age. Glycated hemoglobin was substantially above the normal range (3.8-6.5%) at 3 months of age (14.1%). Glycated hemoglobin significantly declined in the obese WDF rats between 6 and 12 months of age. Nonfasted plasma glucose was significantly elevated in the obese WDF rats at 3 months (14.1 +/- 2.1 mM/L) and 6 months of age (16.2 +/- 2.3 mM/L) compared to lean controls. At 12 months of age there was no difference in plasma glucose between obese and lean WDF rats. Obese and lean Zucker rats had similar levels of GHb and plasma glucose at all ages. In conclusion, GHb provides more integrated data for classifying disease status of WDF rats and evaluation of potential long-term complications associated with hyperglycemia.  相似文献   
19.
20.
OBJECTIVE: This study was undertaken to evaluate a smoking cessation intervention provided to women smokers as follow-up to cervical cancer screening. METHODS: Women who had had a Pap test in the prior month (N = 4,053) were called to complete a survey that assessed smoking status; 580 identified smokers were randomized to receive Usual care (n = 292) or a Self-help intervention (n = 288) that included a self-help booklet, a smoking and reproductive health information card, and three telephone counseling calls. Women were followed up at 6 and 15 months post-base line. RESULTS: Cessation rates in the Usual care (UC) and Self-help (SH) groups did not differ at the 6-month (UC 10.5% vs SH 10.9%, P = 0.56) or 15-month follow-up (UC 15.5% vs SH 10.6%, P = 0.17). Among women with an abnormal Pap test result there were no differences by study group in cessation rates at 6-month (UC 9.8% vs SH 11.0%, P = 0.71) or 15-month follow-up (UC 14.6% vs SH 13.4%, P = 0.96). CONCLUSION: Integrating interventions into the clinical setting and involving providers at the point of care may have greater potential for capitalizing on this "teachable moment." Copyright 1999 American Health Foundation and Academic Press.  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