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   931878篇
  免费   66174篇
  国内免费   1343篇
耳鼻咽喉   12957篇
儿科学   24361篇
妇产科学   23232篇
基础医学   132880篇
口腔科学   28247篇
临床医学   80531篇
内科学   183222篇
皮肤病学   19226篇
神经病学   72166篇
特种医学   36800篇
外国民族医学   79篇
外科学   152065篇
综合类   18042篇
现状与发展   1篇
一般理论   234篇
预防医学   61737篇
眼科学   21307篇
药学   72521篇
  3篇
中国医学   2162篇
肿瘤学   57622篇
  2018年   8959篇
  2017年   7025篇
  2016年   7759篇
  2015年   8856篇
  2014年   11982篇
  2013年   17492篇
  2012年   24079篇
  2011年   25029篇
  2010年   14798篇
  2009年   14262篇
  2008年   24593篇
  2007年   25681篇
  2006年   26470篇
  2005年   25419篇
  2004年   24551篇
  2003年   23596篇
  2002年   23141篇
  2001年   54724篇
  2000年   56542篇
  1999年   46947篇
  1998年   10730篇
  1997年   9464篇
  1996年   9592篇
  1995年   8926篇
  1994年   8278篇
  1993年   7593篇
  1992年   35489篇
  1991年   33912篇
  1990年   32734篇
  1989年   31869篇
  1988年   28991篇
  1987年   28249篇
  1986年   26288篇
  1985年   25144篇
  1984年   17832篇
  1983年   15141篇
  1982年   7796篇
  1981年   6771篇
  1979年   15782篇
  1978年   10598篇
  1977年   9052篇
  1976年   7871篇
  1975年   8628篇
  1974年   10466篇
  1973年   9858篇
  1972年   9357篇
  1971年   8852篇
  1970年   8426篇
  1969年   7923篇
  1968年   7200篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
BACKGROUND: Obsessive-compulsive disorder (OCD) is a chronic, impairing and often comorbid disorder. METHODS: 1000 subjects who called the Anxiety Disorders Association of America (ADAA) were surveyed and divided in three groups: (a) callers with OCD (OCD) and two overlapping control groups: (b) callers with no axis I disorder (NAC) and (c) with no-OCD (NOC) using a 97-item questionnaire. RESULTS: The rate of OCD was 14.5% (N = 145). Relative to the NOC group, OCD subjects were more likely to be female, White, younger and not married. Relative to the NAC group, subjects with OCD were more likely to be White, not married and younger. OCD was accompanied by significant comorbidity and was associated with an increased number of visits to health professionals than NAC subjects. There was no significant difference regarding unemployment rates among the three groups. However, OCD callers were more likely than both control groups to have missed work or have decreased productivity due to their mental condition. OCD subjects took an average of 1 psychotropic medication in the past year and were statistically more likely than the control groups to experience sleepiness and nervousness as side effects. CONCLUSIONS: OCD was fairly prevalent among ADAA callers and presented high levels of comorbidity, impairment, health care utilization and sensitivity to psychotropic side effects.  相似文献   
104.
105.
Introduction Vitamin D plays an important role in bone health. Our purpose was to measure serum 25-hydroxyvitamin D concentrations and their determinants in a national sample (n=2,946) of New Zealanders aged 15 years and over.Findings Mean (99% CI) serum 25-hydroxyvitamin D concentrations were 47 (45–50) nmol/l in women and 52 (49–55) nmol/l in men. Mean concentrations in New Zealand European and Others (NZEO, n=2,440), Mori (n=370), and Pacific (n=136) were 51 (49–53), 42 (38–46) and 37 (33–42) nmol/l, respectively. Three percent of New Zealanders had serum 25-hydroxyvitamin D concentrations indicative of deficiency (≤17.5 nmol/l); 48% and 84% were insufficient based on cutoffs of ≤50 and ≤80 nmol/l. Determinants of serum 25-hydroxyvitamin D concentrations in women were age, ethnicity, obesity, latitude and season; determinants in men were ethnicity and season. Serum 25-hydroxyvitamin D in women declined with age; mean concentration was 13 (8–18) nmol/l lower in women 65 years or older and 9 (5–13) nmol/l lower in women 45–64 years compared with women 15–18 years. Spring to summer differences in serum 25-hydroxyvitamin D were 31 (28–34) and 28 (25–31) nmol/l in women and men, respectively. Obese women had lower vitamin status than normal-weight women by 6 (3–10). Women living in the South Island had a mean serum 25-hydroxyvitamin D that was 6 (3–9) nmol/l lower than women living in the North Island. Ethnicity and season are the major determinants of serum 25-hydroxyvitamin D in New Zealanders.Conclusion The high prevalence of vitamin D insufficiency in New Zealanders, particularly in older women, may warrant strategies to improve vitamin D status.  相似文献   
106.
Inter-individual variations in the development of silicosis, even within the same environments, have been reported, which suggest the contribution of genetic factors in silicosis aetiology. The aim of the present study was to determine whether there is any significant genetic influence on the development of silicosis. Furthermore, which genetic loci are responsible for the pulmonary response to silica exposure? Eight strains of inbred mice were used to examine the genetic influence on the lung fibrotic response to silica exposure. After intercross-breeding between the most susceptible and most resistant strains, a genome-wide linkage analysis of quantitative trait loci (QTL) was performed. Hydroxyproline was applied as an index, and genotypes of 167 marker genes were analysed by fragment analysis using a capillary-type sequencer. There was significant inter-strain difference in the mean concentration of hydroxyproline contents among the eight strains of mice. Breeding studies were conducted between the most susceptible, C57BL/6J, and the most resistant strain, CBA/J. A genome-wide linkage analysis of silica-exposed intercrossed cohorts identified significant QTL on chromosome 4 and suggestive QTL on chromosomes 3 and 18. The present study demonstrates that genetic factors may play a significant role in fibrotic-lung responses to silica; one significant and two suggestive quantitative trait loci were identified.  相似文献   
107.
Zusammenfassung Dieser Artikel stellt eine Übersetzung der im Jahr 2006 herausgegebenen Empfehlungen zur Behandlung von Patienten mit spontaner intrazerebraler Blutung der Europäischen Schlaganfallinitiative (EUSI) für das Europäische Schlaganfall-Council (ESC), die Europäische Neurologische Gesellschaft (ENS) und die Europäische Förderation Neurologischer Gesellschaften (EFNS) dar.Diese EUSI-Empfehlungen werden von dem European Stroke Council (ESC), der European Neurological Society (ENS) und der European Federation of Neurological Societies (EFNS) unterstützt.  相似文献   
108.
Campath-1H (alemtuzumab) induction was used for renal transplantation in combination with sirolimus as immunosuppression. We previously reported a high (28%) rate of early rejection with this regimen, and now report 3-year outcomes. Twenty-nine patients were recipients of either deceased donor or non-HLA (Human Leukocyte Antigen) identical living donor primary renal allografts. Clinical parameters including infection, malignancy, kidney function, and kidney histology were followed prospectively for 3 years. Three-year cumulative graft and patient survival were 96% and 100%, respectively. Twenty patients were maintained on steroid-free immunosuppressive regimens, and 15 patients were maintained on monotherapy for immunosuppression (12 on sirolimus). No serious infectious complications were observed and two patients developed basal cell skin cancer. The 3-year results of our initial pilot study demonstrate good graft (96%) and patient (100%) outcomes. Campath-1H induction has yielded a high proportion of patients maintained on immunosuppressive monotherapy (57%) without serious infectious- and no malignancy-related complications. The reported regimen yielded novel insights into both Campath-1H and sirolimus therapy in renal transplantation. Because of the higher incidence of early rejection, we recommend a modified strategy of immunosuppression including a brief course of a calcineurin inhibitor.  相似文献   
109.
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   
110.
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   
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