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   252008篇
  免费   17863篇
  国内免费   1130篇
耳鼻咽喉   2787篇
儿科学   6496篇
妇产科学   4595篇
基础医学   32939篇
口腔科学   4557篇
临床医学   25323篇
内科学   53622篇
皮肤病学   3383篇
神经病学   24278篇
特种医学   8397篇
外国民族医学   11篇
外科学   38454篇
综合类   3456篇
一般理论   318篇
预防医学   21403篇
眼科学   6559篇
药学   16968篇
  6篇
中国医学   361篇
肿瘤学   17088篇
  2023年   1339篇
  2022年   2412篇
  2021年   5440篇
  2020年   3261篇
  2019年   5300篇
  2018年   5950篇
  2017年   4470篇
  2016年   4959篇
  2015年   5828篇
  2014年   8603篇
  2013年   11795篇
  2012年   18011篇
  2011年   18898篇
  2010年   10578篇
  2009年   9427篇
  2008年   16597篇
  2007年   17451篇
  2006年   17300篇
  2005年   17277篇
  2004年   16191篇
  2003年   15040篇
  2002年   14056篇
  2001年   2102篇
  2000年   1599篇
  1999年   2316篇
  1998年   3065篇
  1997年   2560篇
  1996年   2183篇
  1995年   2095篇
  1994年   1744篇
  1993年   1571篇
  1992年   1256篇
  1991年   1150篇
  1990年   1000篇
  1989年   973篇
  1988年   966篇
  1987年   945篇
  1986年   951篇
  1985年   963篇
  1984年   1218篇
  1983年   1123篇
  1982年   1364篇
  1981年   1312篇
  1980年   1146篇
  1979年   703篇
  1978年   747篇
  1977年   635篇
  1976年   584篇
  1975年   469篇
  1974年   472篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
101.
102.
103.
Ultrasensitive bright field in situ hybridization assays using enzyme metallography (EnzMet) have been developed and validated, but little is known regarding the applicability of EnzMet for immunophenotypic detection of protein via IHC. Superior resolution via discrete metallographic deposits offers the potential for enhancing high-resolution immunophenotyping. Using high-complexity tissue microarrays (TMAs), 88 common solid tumors were evaluated by automated EnzMet (Nanoprobes and Ventana). Targets were chosen to assess the ability of EnzMet to specifically localize encoded antigens in the nucleus (estrogen receptor), cytoplasm (cytokeratins), and cytoplasmic membrane (HER2) in TMAs. Results were compared with conventional IHC diaminobenzidine (DAB) immunostaining. There was full concordance between the EnzMet and conventional IHC results. Furthermore, the EnzMet reaction products did not appreciably diffuse, were dense and sharply defined, and provided excellent high-resolution differentiation of cellular compartments in paraffin sections for the nuclear, cytoplasmic, and cell membrane-localized antigens evaluated. The higher density of elemental silver deposited during enzyme metallography permitted evaluation of core immunophenotypes at a relatively low magnification, allowing more tissue to be screened in an efficient manner. This preliminary study shows the utility of using enzyme metallography for high-resolution immunophenotyping in TMAs.  相似文献   
104.
Dissection of the thoracic aorta is a life-threatening event requiring imaging studies to define the level of the tear and the intinmal flap. The “gold standard” has been angiography. This method may fail to demonstrate the dissection, however, due to overlap of the true and false lumens or a very thin flap that is imaged en face rather than tangentially. Computed tomography has a diagnostic accuracy of 95%, but can fail to image the dissection due to technical factors or a thrombosed false hunen. Magnetic resonance imaging requires a hemodynamically stable and cooperative patient. A diagnostic algorithm is proposed for diagnosis of aortic dissection based on renal function and the surgeon's imaging modality preference.  相似文献   
105.
106.
107.
108.
There is limited information regarding oral health status and other predictors of oral health‐related quality of life. An association between oral health status and perceived oral health‐related quality of life (OHQOL) might help clinicians motivate patients to prevent oral diseases and improve the outcome of some dental public health programs. This study evaluated the relationship between older persons' OHQOL and their functional dentition, caries, periodontal status, chronic diseases, and some demographic characteristics. A group of 733 low‐income elders (mean age 72.7 ISD=4.71, 55.6% women, 55.1% members of ethnic minority groups in the U.S. and Canada) enrolled in the TEETH clinical trial were interviewed and examined as part of their fifth annual visit for the trial. OHQOL was measured by the Geriatric Oral Health Assessment Index (GOHAI); oral health and occlusal status by clinical exams and the Eichner Index; and demographics via interviews. Elders who completed the four‐year assessment had an average of 21.5 teeth (SD=6.9). with 8.5 occluding pairs (SD=4.6), and 32% with occlusal contacts in all four occluding zones. Stepwise multiple regressions were conducted to predict total GOHAI and its subscores (Physical, Social, and Worry). Functional dentition was a less significant predictor than ethnicity and being foreign‐bom. These variables, together with gender, years since immigrating, number of carious roots, and periodontal status, could predict 32% of the variance in total GOHAI, 24% in Physical, 27% in Social, and 21 % in the Worry subscales. These findings suggest that functional dentition and caries influence older adults' OHQOL, but that ethnicity and immigrant status play a larger role.  相似文献   
109.
Alcohol and other drug (AOD) use behaviors of health professions students (HPS) were assessed by surveying both university-based HPS and other nursing programs in a Midwestern state in 1999. Response was 2,646 (56.4%) of surveyed students. Family history of alcohol-related and drug-related problems were reported by 39.8% and 13.9%, respectively, with 42.6% of respondents reporting one or both. Among nursing respondents, 48.1%, 19.2% and 51.1%, respectively, reported family problems with alcohol, drugs, or one or both. Past-year alcohol use was comparable to undergraduate college students (UCS) nationally (83%); heavy drinking, tobacco and recreational drug use by HPS were lower. Past year drug use was highest among medical students. Marijuana was the predominant illicit drug; medical students and males most often reported use. Health professions educational systems should proactively address student AOD prevention, education and assistance needs.  相似文献   
110.
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