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   32454篇
  免费   2238篇
  国内免费   119篇
耳鼻咽喉   241篇
儿科学   1056篇
妇产科学   640篇
基础医学   4414篇
口腔科学   920篇
临床医学   3322篇
内科学   6343篇
皮肤病学   423篇
神经病学   3387篇
特种医学   1240篇
外国民族医学   6篇
外科学   4584篇
综合类   391篇
一般理论   52篇
预防医学   2354篇
眼科学   1124篇
药学   2316篇
中国医学   51篇
肿瘤学   1947篇
  2022年   201篇
  2021年   433篇
  2020年   275篇
  2019年   449篇
  2018年   544篇
  2017年   442篇
  2016年   482篇
  2015年   545篇
  2014年   777篇
  2013年   1270篇
  2012年   1966篇
  2011年   2157篇
  2010年   1164篇
  2009年   1108篇
  2008年   2053篇
  2007年   2347篇
  2006年   2244篇
  2005年   2274篇
  2004年   2162篇
  2003年   2127篇
  2002年   2039篇
  2001年   313篇
  2000年   242篇
  1999年   309篇
  1998年   464篇
  1997年   421篇
  1996年   317篇
  1995年   334篇
  1994年   323篇
  1993年   314篇
  1992年   242篇
  1991年   219篇
  1990年   194篇
  1989年   162篇
  1988年   167篇
  1987年   148篇
  1986年   182篇
  1985年   188篇
  1984年   308篇
  1983年   278篇
  1982年   340篇
  1981年   307篇
  1980年   319篇
  1979年   163篇
  1978年   192篇
  1977年   196篇
  1976年   133篇
  1975年   135篇
  1974年   124篇
  1973年   87篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
OBJECTIVE: The purpose of the study was to determine the incidence of isolated choroid plexus cysts in association with trisomy 18 and other abnormalities.STUDY DESIGN: All patients from June 1992 through December 1995 were followed up after a screening ultrasonography. Any patient with a choroid plexus cyst was offered genetic counseling and an amniocentesis. Screening ultrasonographic examinations were performed on 16,059 patients, and 301 patients had a fetus with a choroid plexus cyst. One hundred thirty patients elected to have an amniocentesis. Patients were followed up to delivery.RESULTS: Two hundred sixty-three patients had an isolated choroid plexus cyst. Thirty-eight patients had a choroid plexus cyst associated with additional risk factors. Risk factors included advanced maternal age, additional ultrasonographic abnormalities, past obstetric history, or family history. No abnormalities were noted in the group with an isolated choroid plexus cyst. Four patients had an abnormality when the choroid plexus cyst was associated with an additional risk factor, including two patients with trisomy 18 and one with trisomy 21.CONCLUSION: An isolated choroid plexus cyst was not associated with a trisomy or other abnormalities in this study. When a choroid plexus cyst was associated with an additional risk factor, 10.5% of the patients had an abnormality. Amniocentesis is recommended when a choroid plexus cyst is found in association with additional risk factors. (Am J Obstet Gynecol 1997;176:1381-3.)  相似文献   
13.
14.
The activity of stereoisomeric [1,2-bis(3-hydroxyphenyl)ethylenediamine] dichloroplatinum(II)-complexes (1-PtCl2,R,S; 2-PtCl2, R,R/S,S; 3-PtCl2, R,R; 4-PtCl2, S,S) on several tumor models (MDA-MB 231 breast cancer cell line; P 388 leukemia, mouse; L 1210 leukemia, mouse; L 5222 leukemia, rat; Ehrlich ascites tumor, mouse--wildtype; cisplatin-, etoposide-, cyclophosphamide-, and daunomycin-resistant, resp.) is described. For comparison the analogous [1,2-bis(4-hydroxyphenyl)ethylendiamine]dichloroplatinum (II)-complexes (5-PtCl2, R, S; 6-PtCl2, R,R/S,S; 7-PtCl2, R,R; 8-PtCl2, S,S) and cisplatin are used. 1-PtCl2 to 4-PtCl2 (OH in 3,3'-positions) show their maximum antitumor effect at lower doses than 5-PtCl2 to 8-PtCl2 (OH in 4,4'-positions). 2-PtCl2 and 6-PtCl2 (R,R/S,S) are more active than 1-PtCl2 and 5-PtCl2 (R,S). 4-PtCl2 and 8-PtCl2 (S,S) are superior to 3-PtCl2 and 7-PtCl2 (R,R). On the L 5222 leukemia 2-PtCl2 (R,R/S,S), 4-PtCl2 (S,S) and 8-PtCl2 (S,S) markedly surpass cisplatin. Strong effects are produced by 2-PtCl2 to 4-PtCl2 on the Ehrlich ascites tumor (wildtype, cisplatin-, etoposide-, cyclophosphamide-, and daunomycin-resistant, resp.). The combination of 4-PtCl2 with cisplatin results in a weakly synergistic effect.  相似文献   
15.
16.
After Chemo     
Pies  Ronald 《JAMA》2007,297(18):1959
  相似文献   
17.
18.
19.
Dietary supplements and nutraceuticals are commonly used by men with erectile dysfunction, decreased libido, BPH, and concerns about developing prostate cancer. Many preparations do not contain the advertised dosages of the active ingredient or are contaminated. Dietary supplements and nutraceuticals, particularly those addressing erectile dysfunction and libido, need to undergo rigorous testing before they can be wholeheartedly recommended.  相似文献   
20.
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