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   1500766篇
  免费   93702篇
  国内免费   3225篇
耳鼻咽喉   20911篇
儿科学   49249篇
妇产科学   42842篇
基础医学   220714篇
口腔科学   42463篇
临床医学   125510篇
内科学   289443篇
皮肤病学   33143篇
神经病学   112310篇
特种医学   61419篇
外国民族医学   455篇
外科学   231326篇
综合类   27442篇
一般理论   358篇
预防医学   111820篇
眼科学   34461篇
药学   110257篇
  2篇
中国医学   2774篇
肿瘤学   80794篇
  2018年   16330篇
  2017年   13673篇
  2016年   14002篇
  2015年   16768篇
  2014年   21247篇
  2013年   30173篇
  2012年   45057篇
  2011年   43282篇
  2010年   25417篇
  2009年   25638篇
  2008年   39353篇
  2007年   42522篇
  2006年   43115篇
  2005年   49653篇
  2004年   49755篇
  2003年   44225篇
  2002年   39287篇
  2001年   64659篇
  2000年   64893篇
  1999年   57644篇
  1998年   15036篇
  1997年   13358篇
  1996年   13649篇
  1995年   12677篇
  1994年   12073篇
  1992年   46602篇
  1991年   46113篇
  1990年   45923篇
  1989年   44279篇
  1988年   41082篇
  1987年   40408篇
  1986年   38559篇
  1985年   36498篇
  1984年   26913篇
  1983年   22912篇
  1982年   12823篇
  1979年   25780篇
  1978年   18053篇
  1977年   15146篇
  1976年   14251篇
  1975年   16595篇
  1974年   19860篇
  1973年   18700篇
  1972年   18053篇
  1971年   17089篇
  1970年   16123篇
  1969年   15277篇
  1968年   14470篇
  1967年   13254篇
  1966年   12083篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
11.
12.
Past research suggests that as many as 50% of onward human immunodeficiency virus (HIV) transmissions occur during acute and recent HIV infection. It is clearly important to develop interventions which focus on this highly infectious stage of HIV infection to prevent further transmission in the risk networks of acutely and recently infected individuals. Project Protect tries to find recently and acutely infected individuals and prevents HIV transmission in their risk networks. Participants are recruited by community health outreach workers at community-based HIV testing sites and drug users' community venues, by coupon referrals and through referrals from AIDS clinics. When a network with acute/recent infection is identified, network members are interviewed about their risky behaviors, network information is collected, and blood is drawn for HIV testing. Participants are also educated and given prevention materials (condoms, syringes, educational materials); HIV-infected participants are referred to AIDS clinics and are assisted with access to care. Community alerts about elevated risk of HIV transmission are distributed within the risk networks of recently infected. Overall, 342 people were recruited to the project and screened for acute/recent HIV infection. Only six index cases of recent infection (2.3% of all people screened) were found through primary screening at voluntary counseling and testing (VCT) sites, but six cases of recent infection were found through contact tracing of these recently infected participants (7% of network members who came to the interview). Combining screening at VCT sites and contact tracing the number of recently infected people we located as compared to VCT screening alone. No adverse events were encountered. These first results provide evidence for the theory behind the intervention, i.e., in the risk networks of recently infected people there are other people with recent HIV infection and they can be successfully located without increasing stigma for project participants.  相似文献   
13.
AimsThe aims were to 1) develop the pharmacokinetics model to describe and predict observed tanezumab concentrations over time, 2) test possible covariate parameter relationships that could influence clearance and distribution and 3) assess the impact of fixed dosing vs. a dosing regimen adjusted by body weight.MethodsIndividual concentration–time data were determined from 1608 patients in four phase 3 studies conducted to assess efficacy and safety of intravenous tanezumab. Patients received two or three intravenous doses (2.5, 5 or 10 mg) every 8 weeks. Blood samples for assessment of tanezumab PK were collected at baseline, 1 h post‐dose and at weeks 4, 8, 16 and 24 (or early termination) in all studies. Blood samples were collected at week 32 in two studies. Plasma samples were analyzed using a sensitive, specific, validated enzyme‐linked immunosorbent assay.ResultsA two compartment model with parallel linear and non‐linear elimination processes adequately described the data. Population estimates for clearance (CL), central volume (V 1), peripheral volume (V 2), inter‐compartmental clearance, maximum elimination capacity (VM) and concentration at half‐maximum elimination capacity were 0.135 l day–1, 2.71 l, 1.98 l, 0.371 l day–1, 8.03 μg day–1 and 27.7 ng ml–1, respectively. Inter‐individual variability (IIV) was included on CL, V 1, V 2 and VM. A mixture model accounted for the distribution of residual error. While gender, dose and creatinine clearance were significant covariates, only body weight as a covariate of CL, V 1 and V 2 significantly reduced IIV.ConclusionsThe small increase in variability associated with fixed dosing is consistent with other monoclonal antibodies and does not change risk : benefit.  相似文献   
14.
There is an increasing number of effective therapies for fracture prevention in adults at risk of osteoporosis. However, shortcomings in the evidence underpinning our management of osteoporosis still exist. Evidence of antifracture efficacy in the groups of patients who most commonly use calcium and vitamin D supplements is lacking, the safety of calcium supplements is in doubt, and the safety and efficacy of high doses of vitamin D give cause for concern. Alendronate, risedronate, zoledronate and denosumab have been shown to prevent spine, nonspine and hip fractures; in addition, teriparatide and strontium ranelate prevent both spine and nonspine fractures, and raloxifene and ibandronate prevent spine fractures. However, most trials provide little information regarding long‐term efficacy or safety. A particular concern at present is the possibility that oral bisphosphonates might cause atypical femoral fractures. Observational data suggest that the incidence of this type of fracture increases steeply with duration of bisphosphonate use, resulting in concern that the benefit–risk balance may become negative in the long term, particularly in patients in whom the osteoporotic fracture risk is not high. Therefore, reappraisal of ongoing use of bisphosphonates after about 5 years is endorsed by expert consensus, and ‘drug holidays’ should be considered at this time. Further studies are needed to guide clinical practice in this area.  相似文献   
15.
16.
17.
Abstract

Objective: To understand the origin of extremely high gonadotropin levels in a perimenopausal woman.

Methods: A 52-year-old woman with a 2?months of amenorrhea followed spontaneous menstrual cycles recovery was referred to our outpatient clinic with elevated follicle-stimulating hormone (FSH, 483 mUI/ml), luteinizing hormone (LH, 475 mUI/ml) and prolactin (PRL, 173?ng/ml). She was known to take levosulpiride. The gonadotropin levels did not fit with the clinical features.

Results: A gonadotroph tumor was ruled out. Further analysis confirmed constantly high FSH, LH and PRL levels. The measurements were repeated using different analytical platforms with different results. After serial dilutions, nonlinearity was present suggesting an immunoassay interference. After post-polyethylene glycol recovery, hormone levels appeared in the normal range. Anti-goat antibodies were recognized in the serum of the patient.

Conclusions: This case report shows a case of falsely abnormal high gonadotropin and PRL levels in a woman during menopause transition. In the clinical practice the evaluation of gonadotropin profile is not recommended at this age, but the abnormal levels stimulated further evaluation. An interference in the assay due to anti-goat antibodies resulted in abnormally high level of FSH and LH. A strict collaboration between clinicians and the laboratory is needed, when laboratory findings do not correspond to clinical findings.  相似文献   
18.
19.
20.
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