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   49023篇
  免费   2563篇
  国内免费   285篇
耳鼻咽喉   676篇
儿科学   955篇
妇产科学   565篇
基础医学   6087篇
口腔科学   1345篇
临床医学   3570篇
内科学   11466篇
皮肤病学   1049篇
神经病学   4306篇
特种医学   2391篇
外国民族医学   1篇
外科学   7406篇
综合类   323篇
一般理论   27篇
预防医学   2117篇
眼科学   1069篇
药学   3114篇
中国医学   126篇
肿瘤学   5278篇
  2023年   269篇
  2022年   506篇
  2021年   899篇
  2020年   563篇
  2019年   734篇
  2018年   908篇
  2017年   803篇
  2016年   970篇
  2015年   986篇
  2014年   1258篇
  2013年   1557篇
  2012年   2560篇
  2011年   2555篇
  2010年   1570篇
  2009年   1298篇
  2008年   2338篇
  2007年   2678篇
  2006年   2422篇
  2005年   2414篇
  2004年   2299篇
  2003年   2278篇
  2002年   2263篇
  2001年   1436篇
  2000年   1526篇
  1999年   1396篇
  1998年   622篇
  1997年   551篇
  1996年   492篇
  1995年   426篇
  1994年   386篇
  1993年   352篇
  1992年   1047篇
  1991年   893篇
  1990年   856篇
  1989年   836篇
  1988年   792篇
  1987年   783篇
  1986年   688篇
  1985年   645篇
  1984年   449篇
  1983年   374篇
  1982年   169篇
  1979年   309篇
  1978年   221篇
  1977年   204篇
  1974年   201篇
  1973年   176篇
  1972年   172篇
  1971年   186篇
  1969年   185篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
A 52‐year‐old Japanese woman who presented with gastrointestinal (GI) bleeding underwent a proximal gastrectomy for a gastrointestinal stromal tumor (GIST) with a foveolar hyperplasia at the apex of the tumor, 4.5 cm in size, located in the upper body of the stomach. Although GIST are often asymptomatic and are found only incidentally, clinical symptoms such as bleeding, abdominal pain, or obstruction, occasionally lead to a premorbid diagnosis. When submucosal tumors present GI bleeding, the source of the bleeding usually is an ulceration of the mucosa over the tumor. However, in the present study, it was thought that the bleeding originated from the region of foveolar hyperplasia.  相似文献   
32.
High-performance liquid chromatography has been used to quantitate benzalkonium chloride (alkylbenzyldimethylammonium chloride) in complex ophthalmic formulations at or below concentration levels of 50 ppm. The method involves a one-step dilution for sample preparation and direct injection; therefore, recovery and/or conversion problems are nonexistent. The assay is quick, specific, reproducible, and simple. This new approach makes routine determinations far simpler than previous methods and is especially useful for product stability studies and quality control procedures.  相似文献   
33.
The stability of factor VIII was studied in plasmas from patients on long-term warfarin therapy. The percent residual factor VIII activity (F.VIII:C) after incubation at 37 degrees C for 4 hr was higher in warfarinized patients than in normal subjects; 76.9 +/- 10.8% (mean +/- SD) of the initial F.VIII:C in the patients versus 61.6 +/- 5.8% in normal subjects (p less than 0.001). On the whole, neither protein C nor vitamin K-dependent coagulation factors except factor VII activity (F.VII:C) correlated with the residual F.VIII:C. There was a negative and weak correlation between the residual F.VIII:C at 4 hr and either the initial F.VIII:C or F.VII:C. Another experiment using protein C depleted plasma showed a relatively enhanced stability of F.VIII:C in the protein C deficiency. These results indicate that factor VIII is more stable in warfarinized plasma, and that protein C and vitamin K-dependent coagulation factors are not the sole, main factor responsible for such a phenomenon.  相似文献   
34.
35.
36.
To achieve prolonged breath-holding, oxygen was administered just before dynamic CT and high resolution lung CT. Oxygen administration has proved to be a supportive means to improve the quality of CT studies.  相似文献   
37.
38.
A 57-year-old female presented with an abnormal Pap smear. Colposcopic examination of the cervix revealed white mucosa with erosion and several areas of black pigmentation. After a colposcopically directed biopsy and loop conization, radical hysterectomy and bilateral salpingo-oophorectomy with pelvic and paraaortic lymphadenectomy were performed. Pathological examination disclosed an invasive squamous cell carcinoma admixed with many dendritic melanocytes. Melanin granules were present within the melanocytes and tumor cells. Although similar tumors have been reported in other sites, this is the first report to our knowledge of a pigmented squamous cell carcinoma of the uterine cervix.  相似文献   
39.
40.
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