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   3108篇
  免费   261篇
  国内免费   12篇
耳鼻咽喉   70篇
儿科学   150篇
妇产科学   33篇
基础医学   496篇
口腔科学   71篇
临床医学   371篇
内科学   668篇
皮肤病学   55篇
神经病学   246篇
特种医学   268篇
外国民族医学   2篇
外科学   317篇
综合类   75篇
预防医学   226篇
眼科学   28篇
药学   191篇
中国医学   1篇
肿瘤学   113篇
  2023年   14篇
  2022年   20篇
  2021年   45篇
  2020年   26篇
  2019年   55篇
  2018年   67篇
  2017年   47篇
  2016年   43篇
  2015年   67篇
  2014年   85篇
  2013年   126篇
  2012年   137篇
  2011年   142篇
  2010年   102篇
  2009年   116篇
  2008年   139篇
  2007年   147篇
  2006年   160篇
  2005年   137篇
  2004年   122篇
  2003年   98篇
  2002年   92篇
  2001年   82篇
  2000年   64篇
  1999年   67篇
  1998年   79篇
  1997年   81篇
  1996年   79篇
  1995年   69篇
  1994年   64篇
  1993年   57篇
  1992年   51篇
  1991年   41篇
  1990年   39篇
  1989年   54篇
  1988年   59篇
  1987年   70篇
  1986年   52篇
  1985年   45篇
  1984年   41篇
  1983年   31篇
  1982年   32篇
  1981年   20篇
  1980年   27篇
  1979年   25篇
  1978年   17篇
  1977年   20篇
  1974年   15篇
  1971年   11篇
  1968年   11篇
排序方式: 共有3381条查询结果,搜索用时 15 毫秒
11.
Preclinical testing in Huntington disease   总被引:1,自引:0,他引:1  
  相似文献   
12.
A controlled trial of acyclovir for chickenpox in normal children   总被引:4,自引:0,他引:4  
BACKGROUND. Chickenpox, the primary infection caused by the varicella-zoster virus, affects more than 3 million children a year in the United States. Although usually self-limited, chickenpox can cause prolonged discomfort and is associated with infrequent but serious complications. METHODS. To evaluate the effectiveness of acyclovir for the treatment of chickenpox, we conducted a multicenter, double-blind, placebo-controlled study involving 815 healthy children 2 to 12 years old who contracted chickenpox. Treatment with acyclovir was begun within the first 24 hours of rash and was administered by the oral route in a dose of 20 mg per kilogram of body weight four times daily for five days. RESULTS. The children treated with acyclovir had fewer varicella lesions than those given placebo (mean number, 294 vs 347; P less than 0.001), and a smaller proportion of them had more than 500 lesions (21 percent, as compared with 38 percent with placebo; P less than 0.001). In over 95 percent of the recipients of acyclovir no new lesions formed after day 3, whereas new lesions were forming in 20 percent of the placebo recipients on day 6 or later. The recipients of acyclovir also had accelerated progression to the crusted and healed stages, less itching, and fewer residual lesions after 28 days. In the children treated with acyclovir the duration of fever and constitutional symptoms was limited to three to four days, whereas in 20 percent of the children given placebo illness lasted more than four days. There was no significant difference between groups in the distribution of 11 disease complications (10 bacterial skin infections and 1 case of transient cerebellar ataxia). Acyclovir was well tolerated, and there was no significant difference between groups in the titers of antibodies against varicella-zoster virus. CONCLUSIONS. Acyclovir is a safe treatment that reduces the duration and severity of chickenpox in normal children when therapy is initiated during the first 24 hours of rash. Whether treatment with acyclovir can reduce the rare, serious complications of chickenpox remains uncertain.  相似文献   
13.
Signaling to NF-kappaB   总被引:30,自引:0,他引:30  
Hayden MS  Ghosh S 《Genes & development》2004,18(18):2195-2224
  相似文献   
14.
Immune response of adults to sequential influenza vaccination   总被引:1,自引:0,他引:1  
Annual immunization against influenza is recommended for numerous individuals, but the antibody response to sequential vaccination has not been well characterized. Levels of hemagglutination-inhibition antibody were measured in adults given either two or three doses of trivalent influenza vaccine at six-month intervals. A significant rise in the number of individuals with antibody titers of greater than or equal to 40 was seen for all three antigens only after initial vaccination. Repeated vaccination was necessary to maintain adequate antibody levels only to the A/Brazil (H1N1) antigen; it did not significantly affect the proportions of individuals with protective levels of antibody to either the A/Bangkok (H3N2) or the B/Singapore 222/79 antigens. These findings do not support the current recommendation for annual immunization when the vaccine formulation has not changed.  相似文献   
15.
16.
Radioiodinated serum albumin has been used as a blood marker to define and quantitate physiological volumes for 12 organs and tissue types. The concentration of gallium-67 in "blood-free" tissues of rats was also determined at various times after intravenous administration. Tissues were divided into two kinetically distinguishable types based on reported nonuniform distribution of the blood marker and the gallium distribution observed in the present study. Gallium distribution into the liver and spleen was observed to be slow, with a discernable accumulation phase followed by monoexponential elimination. In contrast, gallium accumulation into the stomach, small and large intestines, heart, lung, skin/adipose tissue, and muscle was rapid and elimination was monophasic.  相似文献   
17.
Nosocomial transmission of herpes simplex virus (HSV) has been described in intensive care units. A cluster of three patients with HSV wound infections within a 6-week period prompted temporary closure of a burn unit and suggested nosocomial cross infection. However, restriction endonuclease "fingerprint" analysis of the HSV isolates showed them to be genetically and therefore epidemiologically unrelated. This report describes these cases and the use of intravenous acyclovir in the treatment of HSV burn wound infections.  相似文献   
18.
19.
20.
BACKGROUND: Detection and quantification of adenovirus (ADV) in peripheral blood specimens has become an increasingly important tool in the management of immunosuppressed patients. Investigators have described the use of whole blood (WB), peripheral blood mononuclear cells (PBMC), serum and plasma but no studies have compared the utility of these different sample types for use in a clinical diagnostic assay. OBJECTIVES: To determine the optimal blood compartment for quantitative real-time measurement of adenovirus in peripheral blood specimens. STUDY DESIGN: WB, PBMC, and plasma representing 338 samples from 148 patients were tested for ADV by quantitative real-time PCR (qrt-PCR) and the results compared for concordance of both qualitative sensitivity and viral load among positive specimens. RESULTS: There was no significant difference in qualitative sensitivity among the three tested specimen types. Quantitative values of WB and plasma were similar and tended to be greater than those found in PBMC samples. Comparison of consecutive positive samples within individual patients showed that viral loads tracked similarly over time, irrespective of the sample type tested. CONCLUSION: While WB and plasma do not offer a significant increase in sensitivity over PBMC, they may offer benefits in terms of reduced processing costs and laboratory turn around time.  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