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   46445篇
  免费   4113篇
  国内免费   84篇
耳鼻咽喉   641篇
儿科学   1500篇
妇产科学   930篇
基础医学   6470篇
口腔科学   1266篇
临床医学   5120篇
内科学   8255篇
皮肤病学   637篇
神经病学   3934篇
特种医学   1486篇
外国民族医学   1篇
外科学   7220篇
综合类   1009篇
一般理论   39篇
预防医学   4773篇
眼科学   1266篇
药学   2738篇
中国医学   22篇
肿瘤学   3335篇
  2021年   659篇
  2020年   392篇
  2019年   623篇
  2018年   828篇
  2017年   599篇
  2016年   617篇
  2015年   718篇
  2014年   1116篇
  2013年   1605篇
  2012年   2285篇
  2011年   2337篇
  2010年   1321篇
  2009年   1154篇
  2008年   2018篇
  2007年   2235篇
  2006年   2159篇
  2005年   2240篇
  2004年   2036篇
  2003年   1957篇
  2002年   1785篇
  2001年   1312篇
  2000年   1328篇
  1999年   1186篇
  1998年   552篇
  1997年   456篇
  1996年   463篇
  1995年   404篇
  1994年   428篇
  1993年   388篇
  1992年   1050篇
  1991年   911篇
  1990年   852篇
  1989年   863篇
  1988年   791篇
  1987年   738篇
  1986年   729篇
  1985年   709篇
  1984年   572篇
  1983年   516篇
  1982年   391篇
  1981年   416篇
  1980年   337篇
  1979年   570篇
  1978年   472篇
  1977年   347篇
  1975年   348篇
  1974年   450篇
  1973年   404篇
  1972年   366篇
  1971年   328篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
ABSTRACT

Abortion is legal in South Africa, but negative abortion attitudes remain common and are poorly understood. We used nationally representative South African Social Attitudes Survey data to analyze abortion attitudes in the case of fetal anomaly and in the case of poverty from 2007 to 2016 (n = 20,711; ages = 16+). We measured correlations between abortion attitudes and these important predictors: religiosity, attitudes about premarital sex, attitudes about preferential hiring and promotion of women, and attitudes toward family gender roles. Abortion acceptability for poverty increased over time (b = 0.05, p < .001), but not for fetal anomaly (b = ?0.008, p = .284). Highly religious South Africans reported lower abortion acceptability in both cases (Odds Ratio (OR)anomaly = 0.85, p = .015; ORpoverty = 0.84, p = .02). Premarital sex acceptability strongly and positively predicted abortion acceptability (ORanomaly = 2.63, p < .001; ORpoverty = 2.46, p < .001). Attitudes about preferential hiring and promotion of women were not associated with abortion attitudes, but favorable attitudes about working mothers were positively associated with abortion acceptability for fetal anomaly ((ORanomaly = 1.09, p = .01; ORpoverty = 1.02, p = .641)). Results suggest negative abortion attitudes remain common in South Africa and are closely tied to religiosity, traditional ideologies about sexuality, and gender role expectations about motherhood.  相似文献   
5.
Neuroimaging studies using the social-exclusion paradigm Cyberball indicate increased dorsal anterior cingulate cortex (dACC) and right insula activity as a function of exclusion. However, comparatively less work has been done on how social status factors may moderate this finding. This study used the Cyberball paradigm with 85 (45 females) socio-economically diverse participants from a larger longitudinal sample. We tested whether neighborhood quality during adolescence would predict subsequent neural responding to social exclusion in young adulthood. Given previous behavioral studies indicating greater social vigilance and negative evaluation as a function of lower status, we expected that lower adolescent neighborhood quality would predict greater dACC activity during exclusion at young adulthood. Our findings indicate that young adults who lived in low-quality neighborhoods in adolescence showed greater dACC activity to social exclusion than those who lived in higher quality neighborhoods. Lower neighborhood quality also predicted greater prefrontal activation in the superior frontal gyrus, dorsal medial prefrontal cortex and the middle frontal gyrus, possibly indicating greater regulatory effort. Finally, this effect was not driven by subsequent ratings of distress during exclusion. In sum, adolescent neighborhood quality appears to potentiate neural responses to social exclusion in young adulthood, effects that are independent of felt distress.  相似文献   
6.
7.
Objectives: There is a paucity of reporting on surgical outcomes of isolated posterior cruciate ligament reconstruction (PCLR). We hypothesize that isolated PCL injuries failing nonoperative treatment achieve good outcomes and are able to return to sport following PCLR.

Methods: A retrospective analysis was performed to identify patients with isolated PCL injuries that underwent reconstruction between 2001 and 2014. Patients with multi-ligamentous injury or another concomitant knee pathology were excluded. Medical records were reviewed for demographic, clinical and operative data. Patients were contacted for administration of a telephone-based questionnaire which included the International Knee Documentation Committee (IKDC) Subjective Knee Evaluation form, Lysholm-Tegner scales, Marx activity scale (MAS), return to sport status, and patient satisfaction instruments.

Results: A total of 15 isolated PCL reconstructions in 14 patients with a mean age of 27.5 years (range 17–43) met the study inclusion criteria; mean follow up was 6.3 years (range 1.4–15.2). Pre-operatively, the primary complaint was knee instability in all patients; on physical examination, lack of a firm end point during posterior drawer testing was found in 93% (14/15) of the knees. In total, 12 of 15 knees underwent transtibial, single-bundle PCLR and three of 15 underwent tibial inlay, double bundle PCLR. Graft types included: quadriceps autograft (7/15), Achilles allograft (6/15), and hamstring autograft (2/15). There were no graft failures in our patient cohort. At most recent follow up the mean scores respectively on the IKDC form, Lysholm-Tegner scales and MAS were (standard deviation): 77.3 (16.5), 83.1 (17.9), 6.13 (2.6), and 7.1 (6.0). All fourteen patients were athletes prior to their injury and 79% (11/14) returned to sport and overall patient satisfaction was 9.2/10.

Conclusions: Isolated PCLR provides good outcomes at mean medium-term follow up with restoration of function, high rate of return to sport and overall patient satisfaction.  相似文献   

8.
Recent focus on the neonatal intestinal microbiome has advanced our knowledge of the complex interplay between the intestinal barrier, the developing immune system, and commensal and pathogenic organisms. Despite the parallel role of the infant skin in serving as both a barrier and an interface for priming the immune system, large gaps exist in our understanding of the infantile cutaneous microbiome. The skin microbiome changes and matures throughout infancy, becoming more diverse and developing the site specificity known to exist in adults. Delivery method initially determines the composition of the cutaneous microbiome, though this impact appears transient. Cutaneous microbes play a critical role in immune system development, particularly during the neonatal period, and microbes and immune cells have closely intertwined, reciprocal effects. The unique structure of newborn skin influences cutaneous microbial colonization and the development of dermatologic pathology. The development of the infantile skin barrier and cutaneous microbiome contributes to future skin pathology. Atopic dermatitis flares and seborrheic dermatitis have been linked to dysbiosis, while erythema toxicum neonatorum is an immune response to the establishment of normal bacterial skin flora. Physicians who care for infants should be aware of the impact of the infantile skin microbiome and its role in the development of pathology. A better understanding of the origin and evolution of the skin microbiome will lead to more effective prevention and treatment of pediatric skin disease.  相似文献   
9.
10.
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