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   181728篇
  免费   1208篇
  国内免费   47篇
耳鼻咽喉   1176篇
儿科学   6821篇
妇产科学   3123篇
基础医学   17298篇
口腔科学   1676篇
临床医学   12744篇
内科学   32220篇
皮肤病学   780篇
神经病学   16750篇
特种医学   9168篇
外科学   29896篇
综合类   2341篇
预防医学   18205篇
眼科学   2909篇
药学   10082篇
中国医学   676篇
肿瘤学   17118篇
  2023年   38篇
  2021年   166篇
  2020年   93篇
  2019年   152篇
  2018年   22057篇
  2017年   17459篇
  2016年   19637篇
  2015年   1054篇
  2014年   977篇
  2013年   970篇
  2012年   7241篇
  2011年   21330篇
  2010年   18986篇
  2009年   11647篇
  2008年   19730篇
  2007年   21979篇
  2006年   831篇
  2005年   2497篇
  2004年   3693篇
  2003年   4615篇
  2002年   2770篇
  2001年   470篇
  2000年   618篇
  1999年   358篇
  1998年   251篇
  1997年   276篇
  1996年   145篇
  1995年   164篇
  1994年   136篇
  1993年   97篇
  1992年   173篇
  1991年   202篇
  1990年   262篇
  1989年   195篇
  1988年   166篇
  1987年   151篇
  1986年   144篇
  1985年   110篇
  1984年   103篇
  1983年   80篇
  1982年   51篇
  1980年   59篇
  1979年   59篇
  1974年   47篇
  1970年   56篇
  1969年   39篇
  1968年   40篇
  1938年   60篇
  1932年   56篇
  1930年   46篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
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   
52.
53.
Gastroesophageal reflux is the most common benign disorder of the esophagus and laparoscopic Nissen fundoplication has become the standard surgical treatment for its treatment. In our area, where the use of bougie calibration is debatable, postoperative dysphagia is encountered often after this surgery although it is usually not permanent. The aim of this study was to investigate the effect of using a soft silicone tube 39 F in diameter for esophageal calibration during laparoscopic Nissen fundoplication on the incidence of postoperative dysphagia. We divided cases scheduled to undergo laparoscopic Nissen fundoplication between January 2009 and November 2010 into two groups, each consisting 25 patients. Esophageal calibration with a 39 F silicone orogastric tube was used for the first group while there was no operative calibration in the second group. The surgical duration was recorded; the presence and severity of the postoperative dysphagia was calculated by using a dysphagia severity scoring system during the 1-year postoperative follow-up. The dysphagia severity scores were significantly lower in group 1 than group 2 on the postoperative second day and at the end of the first week and first month. We did not find a significant difference at the end of the 6-month and first year. There was also no significant difference regarding surgery duration. The use of a soft orogastric tube 39 F in diameter for esophagus calibration during laparoscopic Nissen fundoplication has significantly decreased the incidence of postoperative transient dysphagia without affecting the duration of surgery. Although dysphagia gradually resolves in the majority of patients, a safe and easy calibration method for its prevention is worth developing, and we believe that the use of our method in larger series could be beneficial.  相似文献   
54.
Manabu Fujimoto  Jun Asai  Yoshihide Asano  Takayuki Ishii  Yohei Iwata  Tamihiro Kawakami  Masanari Kodera  Masatoshi Abe  Masahiro Amano  Ryuta Ikegami  Taiki Isei  Zenzo Isogai  Takaaki Ito  Yuji Inoue  Ryokichi Irisawa  Masaki Ohtsuka  Yoichi Omoto  Hiroshi Kato  Takafumi Kadono  Sakae Kaneko  Hiroyuki Kanoh  Masakazu Kawaguchi  Ryuichi Kukino  Takeshi Kono  Monji Koga  Keisuke Sakai  Eiichi Sakurai  Yasuko Sarayama  Yoichi Shintani  Miki Tanioka  Hideaki Tanizaki  Jun Tsujita  Naotaka Doi  Takeshi Nakanishi  Akira Hashimoto  Minoru Hasegawa  Masahiro Hayashi  Kuninori Hirosaki  Hideki Fujita  Hiroshi Fujiwara  Takeo Maekawa  Koma Matsuo  Naoki Madokoro  Sei-Ichiro Motegi  Hiroshi Yatsushiro  Osamu Yamasaki  Yuichiro Yoshino  Andres James LE Pavoux  Takao Tachibana  Hironobu Ihn  Japanese Dermatological Association Guidelines 《The Journal of dermatology》2020,47(10):1071-1109
The Japanese Dermatological Association prepared guidelines focused on the treatment of skin ulcers associated with connective tissue disease/vasculitis practical in clinical settings of dermatological care. Skin ulcers associated with connective tissue diseases or vasculitis occur on the background of a wide variety of diseases including, typically, systemic sclerosis but also systemic lupus erythematosus (SLE), dermatomyositis, rheumatoid arthritis (RA), various vasculitides and antiphospholipid antibody syndrome (APS). Therefore, in preparing the present guidelines, we considered diagnostic/therapeutic approaches appropriate for each of these disorders to be necessary and developed algorithms and clinical questions for systemic sclerosis, SLE, dermatomyositis, RA, vasculitis and APS.  相似文献   
55.
56.
57.
Relatively young (4-week-old) selenium deficient (SeD) mice, which lack the activity of selenium-dependent glutathione peroxidase (GSH-Px) isomers, were prepared using torula yeast-based SeD diet. Mice were fed the torula yeast-based SeD diet and ultra-pure water. Several different timings for starting the SeD diet were assessed. The weekly time course of liver comprehensive GSH-Px activity after weaning was monitored. Protein expression levels of GPx1 and 4 in the liver were measured by Western blot analysis. Gene expression levels of GPx1, 2, 3, 4, and 7 in the liver were measured by quantitative real-time PCR. Apoptotic activity of thymocytes after hydrogen peroxide (H2O2) exposure was compared. Thirty-day survival rates after whole-body X-ray irradiation were estimated. Pre-birth or right-after-birth starting of the SeD diet in dams was unable to lead to creation of SeD mice due to neonatal death. This suggests that Se is necessary for normal birth and healthy growing of mouse pups. Starting the mother on the SeD diet from 2 weeks after giving birth (SeD-trial-2w group) resulted in a usable SeD mouse model. The liver GSH-Px activity of the SeD-trial-2w group was almost none from 4 week olds, but the mice survived for more than 63 weeks. Protein and gene expression of GPx1 was suppressed in the SeD-trial-2w group, but that of GPx4 was not. The thymocytes of the SeD-trial-2w group were sensitive to H2O2-induced apoptosis. The SeD-trial-2w group was sensitive to whole-body X-ray irradiation compared with control mice. The SeD-trial-2w model may be a useful animal model for H2O2/hydroperoxide-induced oxidative stress.  相似文献   
58.
Myofibroma and myofibromatosis is a well-recognized spindle cell neoplasm that occurs predominantly in infants and young children. They have been described under different names since 1951. These lesions are a benign fibroblast and myofibroblast proliferation containing a biphasic presentation of spindle shaped cells surrounding a central zone of less differentiated cells focally arranged in a hemangiopericytoma like pattern. Classically these lesions are described in children younger than two, with 2/3rd present at birth and rarely in adults. Controversy exists as to an autosomal dominant or recessive inheritance or to a sporadic occurrence. Presented here is a unique case of myofibroma involving the mandible in a 11 year-old male patient. Clinically it mimicked more like a beningn tumor and not exhibiting any of its classical signs. The diagnosis could be established only after complete excision of the lesion and histopathological examination. There was no recurrence after a follow up period of 4 months.  相似文献   
59.
60.
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