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   4383篇
  免费   298篇
  国内免费   5篇
耳鼻咽喉   41篇
儿科学   168篇
妇产科学   71篇
基础医学   464篇
口腔科学   74篇
临床医学   422篇
内科学   636篇
皮肤病学   70篇
神经病学   279篇
特种医学   207篇
外科学   698篇
综合类   180篇
一般理论   4篇
预防医学   460篇
眼科学   321篇
药学   347篇
中国医学   2篇
肿瘤学   242篇
  2022年   27篇
  2021年   56篇
  2020年   40篇
  2019年   65篇
  2018年   70篇
  2017年   54篇
  2016年   57篇
  2015年   68篇
  2014年   81篇
  2013年   129篇
  2012年   203篇
  2011年   230篇
  2010年   132篇
  2009年   113篇
  2008年   204篇
  2007年   191篇
  2006年   193篇
  2005年   202篇
  2004年   176篇
  2003年   183篇
  2002年   140篇
  2001年   143篇
  2000年   157篇
  1999年   162篇
  1998年   68篇
  1997年   57篇
  1996年   53篇
  1995年   56篇
  1994年   46篇
  1993年   50篇
  1992年   97篇
  1991年   105篇
  1990年   86篇
  1989年   91篇
  1988年   94篇
  1987年   90篇
  1986年   73篇
  1985年   62篇
  1984年   48篇
  1983年   41篇
  1982年   31篇
  1981年   40篇
  1980年   22篇
  1979年   48篇
  1978年   37篇
  1977年   32篇
  1975年   28篇
  1974年   27篇
  1973年   23篇
  1972年   39篇
排序方式: 共有4686条查询结果,搜索用时 15 毫秒
71.
72.
Early diagnosis of symptomatic gynecological cancer is likely to improve patient outcomes, including survival. The primary care practitioner has a key role to play in this—they must recognize the symptoms and signs of gynecological cancer and make prompt evidence-based decisions regarding further investigation and referral. However, this is often difficult as many of the symptoms of gynecological cancers are nonspecific and are more likely to be caused by benign rather than malignant disease. As primary care is generally the first point of patient contact, those working in this setting usually encounter cancer patients at an earlier, and possibly less symptomatic, stage than practitioners in secondary care. Despite these challenges, research has improved our understanding of the symptoms patients present to primary care with, and a range of tests and referral pathways now exist in the UK and other countries to aid early diagnosis. Primary care practitioners can also play a key role in gynecological cancer prevention. A significant proportion of gynecological cancer is preventable either through lifestyle changes such as weight loss, or, for cervical cancer, vaccination and/or engagement with screening programs. Primary care provides an excellent opportunity to discuss cancer risk with patients and to promote risk reduction strategies and lifestyle change. In this article, the first in a series discussing cancer detection in primary care, we concentrate on gynecological cancer and focus on the three most common forms that a primary care practitioner is likely to encounter: ovarian, endometrial, and cervical cancer. We outline key risk factors, briefly discuss prevention and screening strategies, and offer practical guidance on the recognition of symptoms and signs and the investigation and referral of women with suspected cancer. While this article is written from a UK primary care perspective, much of what is discussed will be of relevance to those working in other healthcare systems.  相似文献   
73.
74.
BACKGROUND: Interleukin-15 (IL-15) and interleukin-18 (IL-18) are potential regulators of body composition in humans. The authors previously reported that megestrol acetate ingestion causes a large accumulation of adipose tissue and reduces muscle mass. Therefore, the purpose of this investigation was to evaluate the effects of megestrol acetate ingestion on circulating IL-15 and IL-18 concentrations in healthy elderly men. METHODS: All participants received 800 mg of megestrol acetate per day during this 12-week study. Megestrol acetate was combined with testosterone injections (100 mg/week), placebo injections, resistance training, or resistance training and testosterone. Resting IL-15 and IL-18 concentrations were measured by enzyme-linked immunosorbent assay at week 0 (pre), week 6 (mid), and week 12 (post). RESULTS: The time effect for IL-15 was significant (p = .0008), with the mid and post values being significantly greater than the pre value. The change in IL-15 concentration was not significantly related to the change in muscle mass (r = -.31; p > .05), nor was it related to the change in fat mass (r =.17; p > .05). Differences among groups or over time were not significant for IL-18, nor were correlations between pre body weight and pre IL-18 (r = -.03), pre fat mass and pre IL-18 (r = .14), or the change in fat mass and the change in IL-18 (r = -.07). CONCLUSIONS: IL-15 was increased as a result of megestrol acetate ingestion; however, megestrol acetate did not affect circulating IL-18 concentrations, and the change in IL-18 did not correlate with any body composition variables.  相似文献   
75.
A Sheffield family with a predisposition towards thrombosis has been shown to have a functional abnormality of antithrombin. The abnormality was detected as reduced heparin cofactor activity, with normal antigenic levels of antithrombin. Crossed immunoelectrophoresis performed in the absence and presence of heparin was normal. The antithrombin was isolated by heparin Sepharose affinity chromatography. It had normal mobility on SDS polyacrylamide gel electrophoresis. However, the second order rate constant of inhibition of thrombin was about half that of normal, and this was compatible with a heterozygous abnormality involving the reactive site. The antithrombin was further purified by chromatography on thrombin-Sepharose (to remove the normal component), reduced, S-carboxymethylated and fragmented with cyanogen bromide. A pool containing the reactive site region was digested with trypsin and the molecular size of peptides generated determined by fast atom bombardment mass spectrometry. The two peptides adjacent to the Arg393-Ser394 bond of mass 2290 and 700 were almost absent from the mass spectrum, but an additional peptide of mass 2952 was present. Subdigestion with V8 protease reduced the mass of this peptide to 1748. These peptides generated by trypsin and V8 protease were almost identical to those obtained when another variant, antithrombin Glasgow, was treated in the same way (Erdjument et al, 1988). It is concluded that the molecular abnormality of antithrombin Sheffield is identical to that of antithrombin Glasgow, Arg393 to His.  相似文献   
76.
77.
Anatomical Science International - Variants of the axillary artery and brachial plexus were found bilaterally in the axilla of an 86-year-old Asian female. On the left, the cadaver donor had a high...  相似文献   
78.
79.
80.
Background.Biomarkers of progression from latent Mycobacterium tuberculosis infection to active tuberculosis are needed. We assessed correlations between infection outcome and antibody responses in macaques and humans by high-throughput, proteome-scale serological studies. Methods.Mycobacterium tuberculosis proteome microarrays were probed with serial sera from macaques representing various infection outcomes and with single-point human sera from tuberculosis suspects. Fluorescence intensity data were analyzed by calculating Z scores and associated P values. Temporal changes in macaque antibody responses were analyzed by polynomial regression. Correlations between human responses and sputum bacillary burden were assessed by quantile and hurdle regression. Results.Macaque outcome groups exhibited distinct antibody profiles: early, transient responses in latent infection and stable antibody increase in active and reactivation disease. In humans, antibody levels and reactive protein numbers increased with bacillary burden. Responses to a subset of 10 proteins were more tightly associated with disease state than reactivity to the broader reactive proteome. Conclusions.Integration of macaque and human data reveals dynamic properties of antibody responses in relation to outcome and leads to actionable findings for translational research. These include the potential of antibody responses to detect acute infection and preclinical tuberculosis and to identify serodiagnostic proteins for the spectrum of bacillary burden in tuberculosis.  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