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   1094054篇
  免费   76858篇
  国内免费   2969篇
耳鼻咽喉   14560篇
儿科学   33838篇
妇产科学   30291篇
基础医学   151650篇
口腔科学   28857篇
临床医学   93466篇
内科学   224232篇
皮肤病学   21521篇
神经病学   90011篇
特种医学   42766篇
外国民族医学   349篇
外科学   172592篇
综合类   22316篇
现状与发展   2篇
一般理论   533篇
预防医学   82895篇
眼科学   24284篇
药学   77075篇
  1篇
中国医学   2147篇
肿瘤学   60495篇
  2021年   9014篇
  2019年   9514篇
  2018年   12788篇
  2017年   10146篇
  2016年   10856篇
  2015年   12485篇
  2014年   17978篇
  2013年   27362篇
  2012年   37735篇
  2011年   40396篇
  2010年   24066篇
  2009年   22510篇
  2008年   38646篇
  2007年   41036篇
  2006年   40702篇
  2005年   40676篇
  2004年   38991篇
  2003年   37283篇
  2002年   36403篇
  2001年   43254篇
  2000年   44047篇
  1999年   38273篇
  1998年   12547篇
  1997年   11375篇
  1996年   11097篇
  1995年   10230篇
  1994年   9709篇
  1993年   9073篇
  1992年   29392篇
  1991年   28106篇
  1990年   27456篇
  1989年   26296篇
  1988年   24503篇
  1987年   24158篇
  1986年   23198篇
  1985年   22141篇
  1984年   17174篇
  1983年   14841篇
  1982年   9737篇
  1981年   8582篇
  1979年   15386篇
  1978年   11122篇
  1977年   9501篇
  1976年   8931篇
  1975年   9590篇
  1974年   11327篇
  1973年   10767篇
  1972年   10106篇
  1971年   9299篇
  1970年   8937篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
53.
54.
55.
To examine the prevalence of Internet sex networking among men who have sex with men (MSM) in Hong Kong and risk behaviors associated with the behavior, a telephone survey of 15,230 Hong Kong Chinese men aged 18-60 was conducted. Of the 283 active MSM (having engaged in some MSM behaviors in the last 6 months) identified, 17.7% had networked for MSM partners via the Internet in the last 6 months. Younger age (odds ratio [OR] for age < or = 25 vs. age >25 = 4.67, 95% confidence interval [CI] = 2.35-9.28) and being an anal-sex MSM (OR = 4.72, 95% CI=2.36-9.44) were independent predictors of Internet sex networking. Being an Internet sex networker was associated with some risk behaviors such as having contracted a sexually transmitted disease (adjusted OR = 4.79, 95% CI = 1.34-17.11), having had > or = 3 MSM partners (adjusted OR = 4.74, 95% CI = 2.20-10.23), and having engaged in anal sex (adjusted OR = 3.95, 95% CI = 1.89-8.23). HIV prevention programs for MSM should thereby include Internet-based interventions.  相似文献   
56.
57.
Atherosclerotic renal artery stenosis (ARAS) may cause hypertension, progressive renal failure, and recurrent pulmonary edema. It typically occurs in high risk patients with coexistent vascular disease elsewhere. Most patients with ARAS are likely to die from coronary heart disease or stroke before end-stage renal failure occurs. Recent controlled trials have shown that most patients undergoing angioplasty to treat renovascular hypertension still need antihypertensive agents 6 or 12 months after the procedure. Nevertheless, the number of antihypertensive agents required to control blood pressure adequately is lower following angioplasty than for medication alone. Trials assessing the value of revascularization for preserving renal function or preventing clinical events are only in the early recruitment phase. Revascularization should be undertaken in patients with ARAS and resistant hypertension or heart failure, and probably in those with rapidly deteriorating renal function or with an increase in plasma creatinine levels during angiotensin-converting enzyme inhibition. With or without revascularization, medical therapy using antihypertensive, hypolipidemic and antiplatelet agents is necessary in almost all cases.  相似文献   
58.
The involvement of oxidative stress in polymorphonuclear leukocytes (PMN) in the pathogenesis of hypertension remains to be elucidated. We analyzed the generation of reactive oxygen species (ROS) by the circulating and peritoneally infiltrating PMN from spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY). Flow cytometric analysis revealed that ROS generation by PMN from SHR was higher than that from WKY before (at 6 weeks of age) and after (at 16 weeks of age) the onset of hypertension. In vivo, ROS generation by PMN from SHR, but not that by PMN from WKY, was significantly suppressed by 10-week treatment with 50 mg/kg/day carvedilol, and this treatment did not affect blood pressure. Western blotting analysis revealed that protein kinase C alpha (PKCalpha), but not PKCbetaI or betaII, was activated more strongly in PMN from SHR than in PMN from WKY. Furthermore, expression of p47phox of nicotinamide adenine dinucleotide phosphate oxidase, but not of p67phox, in PMN from SHR was higher than that in PMN from WKY. These results suggest that ROS generation by PMN is principally enhanced in SHR through activation of PKCalpha and p47phox.  相似文献   
59.
We report the case of a patient with a 13-year history of pemphigus vulgaris (PV) treated with immunosuppressive agents, prednisone and mycophenolate mofetil who had developed lesions of Kaposi's sarcoma (KS) on a sole plaque of PV that had been previously treated with intralesional injections of steroids. The lesions were surgically removed and polymerase chain reaction (PCR) demonstrated human herpesvirus-8 (HHV-8) DNA. There were neither recurrences nor later dissemination of KS following gradual decrease of the immunosuppressive therapy. We suggest that the treatment with intralesional steroids may have influenced the local reactivation of a latent infection of the virus, determining the appearance of this localized KS.  相似文献   
60.
OBJECTIVE: To assess the effects of adding combined estradiol/norethisterone acetate therapy (CENT) to goserelin acetate treatment (GA) of dysfunctional uterine bleeding (DUB) in perimenopausal women. METHODS: In a randomized, placebo-controlled, double-blind trial followed by an open follow-up study, 31 perimenopausal women with DUB were recruited from gynecological outpatient departments of two Dutch hospitals and randomized for treatment with either GA/placebo or GA/CENT for 6 months followed by 18 months of GA/CENT for all. The main outcome measures were abdominal pain, number of bleeding days, double-layer endometrial thickness (DET), Greene climacteric score (GCS), visual analog scale for well-being, bone mineral density (BMD) and mammographic density (BI-RAD score). RESULTS: Abdominal pain, number of bleeding days and DET decreased in both groups, the between-group difference in decrease not being statistically significant. GCS initially showed significant improvement in the GA/CENT group. BMD decreased significantly in the GA/placebo group (-4.1%) compared with the GA/CENT group (-0.3%). Another 18 months of GA/CENT did not result in a lasting difference in BMD between groups. BI-RAD scores did not differ significantly between or within the two groups. CONCLUSIONS: Adding CENT to GA treatment for DUB in perimenopausal women initially prevented BMD loss and improved climacteric complaints, while having no negative impact on vaginal bleeding, abdominal pain or BI-RAD scores. However, prolonged treatment did not result in a lasting prevention of bone loss.  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