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   294818篇
  免费   22509篇
  国内免费   1188篇
耳鼻咽喉   3363篇
儿科学   7652篇
妇产科学   5864篇
基础医学   39294篇
口腔科学   5775篇
临床医学   30681篇
内科学   61045篇
皮肤病学   3954篇
神经病学   27793篇
特种医学   10320篇
外国民族医学   12篇
外科学   44001篇
综合类   4282篇
一般理论   341篇
预防医学   26316篇
眼科学   7570篇
药学   20235篇
  8篇
中国医学   414篇
肿瘤学   19595篇
  2023年   1455篇
  2022年   2651篇
  2021年   5998篇
  2020年   3564篇
  2019年   5861篇
  2018年   6598篇
  2017年   5006篇
  2016年   5502篇
  2015年   6436篇
  2014年   9434篇
  2013年   13071篇
  2012年   19868篇
  2011年   20833篇
  2010年   11629篇
  2009年   10298篇
  2008年   18218篇
  2007年   19208篇
  2006年   19051篇
  2005年   18989篇
  2004年   17756篇
  2003年   16481篇
  2002年   15562篇
  2001年   3675篇
  2000年   3282篇
  1999年   3727篇
  1998年   3645篇
  1997年   3017篇
  1996年   2647篇
  1995年   2563篇
  1994年   2144篇
  1993年   1988篇
  1992年   2490篇
  1991年   2287篇
  1990年   2132篇
  1989年   2021篇
  1988年   1943篇
  1987年   1927篇
  1986年   1845篇
  1985年   1857篇
  1984年   1903篇
  1983年   1729篇
  1982年   1783篇
  1981年   1681篇
  1980年   1528篇
  1979年   1355篇
  1978年   1257篇
  1977年   1036篇
  1976年   977篇
  1975年   834篇
  1974年   919篇
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
81.
Abstract

Objective

Two similarly designed studies compared user experiences with a second-generation extra-thin-wall, 5-bevel 32?G?×?4?mm pen needle (PN) with redesigned hub versus four thinner commercially available PNs.  相似文献   
82.
83.
84.
85.
Inbred mouse strains are the most widely used mammalian model organism in biomedical research owing to ease of genetic manipulation and short lifespan; however, each inbred strain possesses a unique repertoire of deleterious homozygous alleles that can make a specific strain more susceptible to a particular disease. In the current study, we report dystrophic cardiac calcinosis (DCC) in C.B‐17 SCID male mice at 10 weeks of age with no significant change in cardiac function. Acquisition of DCC was characterized by myocardial injury, fibrosis, calcification, and necrosis of the tissue. At 10 weeks of age, 38% of the C.B‐17 SCID mice from two different commercial colonies exhibited significant calcinosis on the ventricular epicardium, predominantly on the right ventricle. The frequency of calcinosis was more than 50% for mice obtained from Taconic's Cambridge City colony and 25% for mice obtained from Taconic's German Town colony. Interestingly, the DCC phenotype did not affect cardiac function at 10 weeks of age. No differences in echocardiography or electrocardiography were observed between the calcinotic and non‐calcinotic mice from either colony. Our findings suggest that C.B‐17 SCID mice exhibit DCC as early as 10 weeks of age with no significant impact on cardiac function. This strain of mice should be cautiously considered for the study of cardiac physiology.  相似文献   
86.
87.
88.
89.
Conclusion: Recurrent respiratory papillomatosis (RRP) patients with high surgical treatment frequency (≥ 1/year, HF) were significantly younger and had a more widespread laryngeal disease compared to a low frequency treated group (< 1 treatment/year, LF). This study confirms the existence of a clinical RRP group, not primarily related to HPV sub-type, but more care-intensive and in need of more vigilant follow-up. Objectives: RRP is associated with high morbidity due to its influence on breathing and voice. The purpose of this study was to characterize RRP patients in northern Sweden and investigate possible predictor factors affecting therapeutic needs. Method: Patients from the regional referral area (northern Sweden) were categorized for age, disease duration, juvenile or adult onset, profile of disease development, number of surgical sessions in relation to disease duration, laryngeal deposition of papilloma, gender, and HPV sub-types, in order to identify patients with increased need for frequent surgical treatment. Results: The median age of the RRP patients (n = 48) was 44.5 years; 34 (71%) were males and 14 (29%) females, most were infected with HPV 6. Patients with high surgical treatment frequency/year were significantly younger and showed more widespread papillomatous vegetation in the larynx, compared to the low frequency treated group.  相似文献   
90.
Contraceptive use is an important strategy for the prevention of unwanted pregnancy and avoidance of induced abortion. Of all the contraception methods, emergency contraceptive (EC) offers the last chance to achieve this. However, few studies have documented the use of EC among young people in Ghana. This study explored knowledge and usage of EC as well as the factors associated with it among University of Cape Coast students. Data were obtained on the knowledge and usage of ECs among University of Cape Coast students in 2013. Logistic regression analysis was used to investigate the association between students’ socio-demographic characteristics and EC knowledge and use. More male students (72 %) than females (59 %) were sexually active. Fifty-seven percent of the respondents had ever heard of EC and 36 % had ever used EC. Although males were more likely to be sexually active, females were more likely to have knowledge of EC use compared to males. The study underscores the need to increase awareness regarding EC among University students in order to offer them the opportunity that EC provides if other forms of contraceptives are missed.  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