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   210817篇
  免费   3067篇
  国内免费   208篇
耳鼻咽喉   1542篇
儿科学   7688篇
妇产科学   3922篇
基础医学   20004篇
口腔科学   2729篇
临床医学   15476篇
内科学   38532篇
皮肤病学   1346篇
神经病学   18474篇
特种医学   10139篇
外国民族医学   4篇
外科学   35302篇
综合类   3161篇
现状与发展   3篇
一般理论   28篇
预防医学   20406篇
眼科学   4044篇
药学   12225篇
  1篇
中国医学   901篇
肿瘤学   18165篇
  2023年   422篇
  2022年   1078篇
  2021年   1689篇
  2020年   1013篇
  2019年   1315篇
  2018年   23245篇
  2017年   18309篇
  2016年   20527篇
  2015年   2211篇
  2014年   2483篇
  2013年   2813篇
  2012年   9980篇
  2011年   23823篇
  2010年   20330篇
  2009年   12851篇
  2008年   21504篇
  2007年   23732篇
  2006年   2544篇
  2005年   3926篇
  2004年   4935篇
  2003年   5634篇
  2002年   3611篇
  2001年   642篇
  2000年   735篇
  1999年   456篇
  1998年   396篇
  1997年   338篇
  1996年   228篇
  1995年   206篇
  1994年   192篇
  1993年   142篇
  1992年   201篇
  1991年   257篇
  1990年   258篇
  1989年   205篇
  1988年   164篇
  1987年   156篇
  1986年   117篇
  1985年   157篇
  1984年   102篇
  1983年   72篇
  1982年   79篇
  1981年   56篇
  1980年   80篇
  1979年   55篇
  1978年   49篇
  1974年   58篇
  1938年   63篇
  1932年   57篇
  1930年   48篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
OBJECTIVE: To introduce 1,1,1,2 tetrafluoroethane (TFE), as a new material for cryosurgery of gingival melanin pigmentation (GMP). STUDY DESIGN: Twenty-one patients with GMP were treated using a TFE-cooled cotton swab. Standard digital images of pigmented areas were measured preoperatively and postoperatively with image-analyzing software. The Mann-Whitney U test was used for statistical analysis. RESULTS: Keratinization was completed 3 to 4 weeks after application, without any trace of pigmentation. Statistical analysis revealed a significant difference between preoperative and postoperative measurements of pigmented areas (P < .05). During the follow-up period, no side effects were observed and improved esthetics were maintained up to month 30. CONCLUSIONS: The clinical outcomes of cryosurgery with TFE for treatment of GMP are very satisfactory. The use of TFE for cryosurgical treatment of GMP is practical and inexpensive. Moreover, unlike other cryosurgery methods no special equipment is required, and it is safe to store in the dental clinic.  相似文献   
13.
For persons battling HIV/AIDS a stable place to live may decide the length and quality of life itself. It is nearly impossible for a person on the streets to engage in a needed continuous AIDS treatment regimen when the very basic question of where that person will rest his or her head when darkness comes in just a few hours is unresolved. When danger lurks on the streets, when cold numbs the limbs, when tiredness overwhelms the mind, when fear breaks the spirit, a place to call home would make all the difference.  相似文献   
14.
BACKGROUND: Chronic hyperplastic candidosis (CHC) represents a chronic opportunistic candida infection. We clarified the presence, localization and participation of alpha-defensin-1 in host response against chronic candidal stimulus. METHODS: Immunohistochemically stained CHC biopsies (n = 10) were compared to candida negative idiopathic leukoplakia (n = 10). RESULTS: In CHC alpha-defensin-1 was detected in neutrophils intravascularly, in lamina propria and in the epithelium, in part in intraepithelial microabscesses. Staining intensity of individual neutrophils varied and was associated with peri- and extracellular staining, in particular in the superficial epithelial cell layers. In controls only very few homogeneously staining neutrophils were detected intravascularly without any extracellular alpha-defensin-1 deposition. CONCLUSIONS: Neutrophils form microabscesses and respond to Candida by activation and release of alpha-defensin-1 to peri- and extracellular matrix. This together with the epithelial cell migration from the basal layer to epithelial surface leads to alpha-defensin-1 rich protective shield in the most superficial epithelial cell layers.  相似文献   
15.
16.
BACKGROUND: The dopamine transporter (DAT) is known to be a key regulator of dopamine, and recent studies of genetics, treatment, and imaging have highlighted the role of DAT in attention-deficit/hyperactivity disorder (ADHD). The findings of in vivo neuroimaging of DAT in ADHD have been somewhat discrepant, however. METHOD: Dopamine transporter binding was measured using a highly selective ligand (C-11 altropane) and positron emission tomography (PET). The sample consisted of 47 well-characterized, treatment-na?ve, nonsmoking, non-comorbid adults with and without ADHD. Additionally, control subjects had few symptoms of ADHD. RESULTS: Results showed significantly increased DAT binding in the right caudate in adults with ADHD compared with matched control subjects without this disorder. CONCLUSIONS: These results confirm abnormal DAT binding in the striatum of adults with ADHD and provide further support that dysregulation of DAT may be an important component of the pathophysiology of ADHD.  相似文献   
17.
18.

Background  

Health service policy in the United Kingdom emphasises the importance of self-care by patients with chronic conditions. Written information for patients about their condition is seen as an important aid to help patients look after themselves. From a discourse analysis perspective written texts such as patient information leaflets do not simply describe the reality of a medical condition and its management but by drawing on some sorts of knowledge and evidence rather than others help construct the reality of that condition. This study explored patient information leaflets on osteoarthritis (OA) to see how OA was constructed and to consider the implications for self-care.  相似文献   
19.
20.

Background  

Total hip arthroplasty is a successful surgery, that fails at a rate of approximately 10% at ten years from surgery. Causes for failure are mainly aseptic loosening of one or both components partially due to wear of articular surfaces and partially to design. The present analysis aimed to identify risk factors and quantify their effects on aseptic failure.  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