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   1566篇
  免费   107篇
  国内免费   11篇
耳鼻咽喉   20篇
儿科学   45篇
妇产科学   42篇
基础医学   154篇
口腔科学   39篇
临床医学   125篇
内科学   319篇
皮肤病学   57篇
神经病学   66篇
特种医学   41篇
外国民族医学   3篇
外科学   247篇
综合类   44篇
预防医学   205篇
眼科学   57篇
药学   130篇
中国医学   5篇
肿瘤学   85篇
  2023年   15篇
  2022年   49篇
  2021年   67篇
  2020年   41篇
  2019年   44篇
  2018年   62篇
  2017年   60篇
  2016年   40篇
  2015年   45篇
  2014年   62篇
  2013年   84篇
  2012年   117篇
  2011年   111篇
  2010年   81篇
  2009年   57篇
  2008年   69篇
  2007年   66篇
  2006年   60篇
  2005年   56篇
  2004年   52篇
  2003年   44篇
  2002年   30篇
  2001年   49篇
  2000年   43篇
  1999年   28篇
  1998年   11篇
  1997年   12篇
  1996年   13篇
  1995年   8篇
  1993年   5篇
  1992年   5篇
  1991年   19篇
  1990年   13篇
  1989年   19篇
  1988年   8篇
  1987年   5篇
  1986年   16篇
  1985年   14篇
  1984年   6篇
  1983年   11篇
  1982年   7篇
  1980年   6篇
  1979年   6篇
  1978年   16篇
  1975年   6篇
  1974年   8篇
  1973年   5篇
  1970年   4篇
  1968年   3篇
  1965年   6篇
排序方式: 共有1684条查询结果,搜索用时 31 毫秒
81.
82.
83.
Denutrition is frequent among HIV-infected (HIV+) adults in sub-Saharan Africa. One of the risk factors for denutrition is a reduction in dietary intake. Eating disorders may be partly responsible for such decreases in food intake. We prospectively analyzed the frequency, associated factors and progression of anorexia, dysphagia and food aversion in a cohort of 330 HIV-infected adults included in a trial of early chemoprophylaxis with cotrimoxazole in Abidjan, Ivory Coast. Patients were followed-up by means of scheduled monthly visits. Eating disorders were assessed using a standardized questionnaire after 6, 12 and 18 months of follow-up. After six months of follow-up, 28% of the patients reported anorexia, 9% dysphagia and 28% food aversion. Multivariate analysis showed that anorexia was significantly more frequent in women than in men (odds ratio (OR) = 2.0 [95% confidence interval: 1.2-3.5]) and in patients with a CD4+ lymphocyte count < 200/mm3 (OR = 1.8 [1.0-3.5]). The risk of dysphagia was also higher for women than for men (OR = 1.8 [1.0-3.5]). The risk of dysphagia was also higher for women than for men (OR = 3.3 [1.3-8.4]). Patients with < 200 CD4+ lymphocytes/mm3 were more likely than those with CD4+ lymphocyte counts of over 200 to suffer food aversion (OR = 1.8 [1.1-3.0]). We analyzed the progression of dietary problems during follow-up and found that anorexia and dysphygia tended to disappear from one evaluation to the next whereas the number of patients reporting food aversion tended to increase. For patients reporting anorexia at the 6-month evaluation, significantly more women than men reported the persistence of anorexia at the 12-month evaluation (16% versus 5%; p = 0.03). Among patients with dysphagia at six months, those with a CD4+ lymphocyte count below 200/mm3 were much more likely than those with a CD4+ count above 200 to report persistent dysphagia at the 12-month evaluation (7% versus 0%; p = 0. 02, Fischer's exact test). For patients with no dietary problems after six months, those taking cotrimoxazole were significantly more likely than those of the placebo group to report food aversion at the 12-month evaluation (21% versus 8%; p = 0.01). We found that dietary problems were associated more with the stage of immunodeficiency that with socioeconomic factors, with the exception of sex, which was associated with several outcomes. These data stress the importance of detecting these frequent dietary problems as part of the overall clinical management of HIV+ adults in Africa, and of providing affected individuals with early nutritional counseling.  相似文献   
84.
PURPOSE: To investigate a case of severe wrinkled corneal flap after laser in situ keratomileusis (LASIK) successfully treated by hydrating the flap with deionized water and applying a bandage contact lens. METHODS: A 39-year-old woman presented with corneal flap wrinkles 24 hours after undergoing LASIK in her left eye. Under the operating microscope the flap was refloated and hydrated with sterile deionized water for 2 minutes without stretching or ironing the flap. A bandage contact lens was then applied for 24 hours. Sterile deionized water was used topically every 2 hours for 1 day. RESULTS: Twenty-four hours after treatment with sterile deionized water and a bandage contact lens, the cornea was smooth and wrinkle free. CONCLUSIONS: Hydration with deionized water may offer advantages over isotonic solutions in treating a wrinkled corneal flap after LASIK.  相似文献   
85.
86.
87.
OBJECTIVE: To outline the major methodological issues appropriate to the use of the population impact number (PIN) and the disease impact number (DIN) in health policy decision making. DESIGN: Review of literature and calculation of PIN and DIN statistics in different settings. SETTING: Previously proposed extensions to the number needed to treat (NNT): the DIN and the PIN, which give a population perspective to this measure. Main results: The PIN and DIN allow us to compare the population impact of different interventions either within the same disease or in different diseases or conditions. The primary studies used for relative risk estimates should have outcomes, time periods and comparison groups that are congruent and relevant to the local setting. These need to be combined with local data on disease rates and population size. Depending on the particular problem, the target may be disease incidence or prevalence and the effects of interest may be either the incremental impact or the total impact of each intervention. For practical application, it will be important to use sensitivity analyses to determine plausible intervals for the impact numbers. CONCLUSIONS: Attention to various methodological issues will permit the DIN and PIN to be used to assist health policy makers assign a population perspective to measures of risk.  相似文献   
88.
89.
Cutaneous aging is a complex biological phenomenon affecting the different constituents of the skin. To compare the effects of intrinsic and extrinsic aging processes, a total of 83 biopsies were collected from sun-exposed and protected skin of healthy volunteers representing decades from the 1st to the 9th (6-84 years of age). Routine histopathology coupled with computer-assisted image analysis was used to assess epidermal changes. Immunoperoxidase techniques with antibodies against type I and type III collagens and elastin were used to quantitatively evaluate changes in collagen and elastic fibers and their ultrastructure was examined by transmission electron microscopy. Epidermal thickness was found to be constant in different decades in both sun-exposed and protected skin; however, it was significantly greater in sun-exposed skin (P = 0.0001). In protected skin, type I and III collagen staining was altered only after the 8th decade, while in sun-exposed skin the relative staining intensity significantly decreased from 82.5% and 80.4% in the 1st decade to 53.2% and 44.1% in the 9th decade, respectively (P = 0.0004 and 0.0008). In facial skin the collagen fiber architecture appeared disorganized after the 4th decade. The staining intensity of elastin in protected skin significantly decreased from 49.2% in the 1st decade to 30.4% in the 9th decade (P = 0.05), whereas in sun-exposed skin the intensity gradually increased from 56.5% in the 1st decade to 75.2% in the 9th decade (P = 0.001). The accumulated elastin in facial skin was morphologically abnormal and appeared to occupy the areas of lost collagen. Collectively, the aging processes, whether intrinsic or extrinsic, have both quantitative and qualitative effects on collagen and elastic fibers in the skin.  相似文献   
90.
The target-derived factors necessary for promoting initial outgrowth from the statoacoustic ganglion (SAG) to the inner ear have not been fully characterized. In the present study, conditioned medium from embryonic Immortomouse inner ear cell lines that maintain many characteristics of developing inner ear sensory epithelia were screened for neurite-promoting activity. Conditioned medium found to be positive for promoting SAG neurite outgrowth and neuronal survival was then tested for the presence of chemokines, molecules that have not previously been investigated for promoting SAG outgrowth. One candidate molecule, monocyte chemotactic protein 1 (MCP-1), was detected in the conditioned medium and subsequently localized to mouse hair cells by immunocytochemistry. In vitro studies demonstrated that function-blocking MCP-1 antibodies decreased the amount of SAG neurite outgrowth induced by the conditioned medium and that subsequent addition of MCP-1 protein was able to promote outgrowth when added to the antibody-treated conditioned medium. The use of the Immortomouse cell lines proved valuable in identifying this candidate cofactor that promotes outgrowth of early-stage SAG nerve fibers and is expressed in embryonic hair cells.  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