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   31581篇
  免费   2102篇
  国内免费   116篇
耳鼻咽喉   238篇
儿科学   1015篇
妇产科学   631篇
基础医学   4247篇
口腔科学   947篇
临床医学   3216篇
内科学   6047篇
皮肤病学   415篇
神经病学   3326篇
特种医学   1143篇
外国民族医学   6篇
外科学   4477篇
综合类   371篇
一般理论   51篇
预防医学   2296篇
眼科学   1121篇
药学   2275篇
中国医学   51篇
肿瘤学   1926篇
  2022年   194篇
  2021年   417篇
  2020年   267篇
  2019年   435篇
  2018年   529篇
  2017年   432篇
  2016年   477篇
  2015年   530篇
  2014年   746篇
  2013年   1250篇
  2012年   1909篇
  2011年   2100篇
  2010年   1135篇
  2009年   1089篇
  2008年   2005篇
  2007年   2281篇
  2006年   2192篇
  2005年   2223篇
  2004年   2113篇
  2003年   2099篇
  2002年   2001篇
  2001年   266篇
  2000年   212篇
  1999年   279篇
  1998年   454篇
  1997年   406篇
  1996年   309篇
  1995年   327篇
  1994年   316篇
  1993年   307篇
  1992年   221篇
  1991年   200篇
  1990年   179篇
  1989年   152篇
  1988年   153篇
  1987年   143篇
  1986年   177篇
  1985年   181篇
  1984年   290篇
  1983年   264篇
  1982年   336篇
  1981年   305篇
  1980年   319篇
  1979年   158篇
  1978年   189篇
  1977年   199篇
  1976年   126篇
  1975年   131篇
  1974年   114篇
  1973年   88篇
排序方式: 共有10000条查询结果,搜索用时 0 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