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   222篇
  免费   30篇
  国内免费   5篇
耳鼻咽喉   1篇
儿科学   16篇
妇产科学   3篇
基础医学   49篇
口腔科学   10篇
临床医学   30篇
内科学   45篇
皮肤病学   3篇
神经病学   10篇
特种医学   27篇
外科学   11篇
综合类   29篇
预防医学   10篇
眼科学   3篇
药学   4篇
肿瘤学   6篇
  2022年   4篇
  2021年   8篇
  2019年   1篇
  2018年   4篇
  2017年   2篇
  2016年   2篇
  2015年   4篇
  2014年   11篇
  2013年   5篇
  2012年   7篇
  2011年   6篇
  2010年   6篇
  2009年   9篇
  2008年   10篇
  2007年   10篇
  2006年   7篇
  2005年   6篇
  2004年   4篇
  2003年   5篇
  2002年   3篇
  2001年   4篇
  2000年   4篇
  1999年   5篇
  1998年   17篇
  1997年   14篇
  1996年   13篇
  1995年   8篇
  1994年   9篇
  1993年   8篇
  1992年   2篇
  1991年   2篇
  1990年   3篇
  1989年   2篇
  1988年   8篇
  1987年   4篇
  1986年   7篇
  1985年   1篇
  1984年   3篇
  1983年   4篇
  1982年   1篇
  1981年   4篇
  1979年   6篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1975年   3篇
  1974年   1篇
  1972年   1篇
  1970年   1篇
  1967年   2篇
排序方式: 共有257条查询结果,搜索用时 15 毫秒
71.
72.
Hematopoietin-1 (H-1) was purified from the human cell line 5637 and two amino acid sequences were observed in the preparation. One sequence was identical to that of interleukin 1 alpha (IL 1 alpha) and the other to that of IL 1 beta. The action of recombinant IL 1 alpha and other hematopoietic growth factors was studied using (a) a high proliferative potential colony-forming cell assay that uses primitive hematopoietic precursors from bone marrow, and (b) a spleen colony-forming unit assay. The results indicate that the IL 1 alpha target cell population is different than the target cell populations of IL 3, granulocyte- macrophage colony-stimulating factor; that IL 1 alpha in combination with mononuclear phagocyte colony-stimulating factor provides a proliferative stimulus; and that IL 1 alpha has at least a survival- enhancing and possibly proliferation-inducing effect on primitive hematopoietic stem cells.  相似文献   
73.
74.
Chou  HC; Ozawa  S; Fu  PP; Lang  NP; Kadlubar  FF 《Carcinogenesis》1998,19(6):1071-1076
Methyl-hydroxylated metabolites of the potent carcinogen, 7,12- dimethylbenz[a]anthracene (DMBA), namely, 7-hydroxymethyl-12- methylbenz[a]anthracene (7-OH-DMBA), 7-methyl-12- hydroxymethylbenz[a]anthracene (12-OH-DMBA) and 7,12- dihydroxymethylbenz[a]anthracene (7,12-diOH-DMBA), were examined as substrates for sulfotransferase bioactivation in different human tissue cytosols. Hepatic cytosols, which were able to catalyze the 3'- phosphoadenosine 5'-phosphosulfate (PAPS)-dependent DNA binding of 7-OH- DMBA, 12-OH-DMBA and 7,12-diOH-DMBA, were highly sensitive to inhibition by dehydroepiandrosterone (DHEA), a specific substrate for human DHEA-steroid sulfotransferase (IC50 = 5 microM). By comparison, 2,6-dichloro-4-nitrophenol, a potent inhibitor of the thermostable (TS)- phenol and estrogen sulfotransferases, did not have an appreciable inhibitory effect. Neither p-nitrophenol, a high affinity substrate for human TS-phenol and estrogen sulfotransferases, nor dopamine, a specific substrate for the thermolabile (TL)-phenol sulfotransferase, significantly inhibited the DNA binding of 12-OH-DMBA catalyzed by hepatic cytosols. Inter-subject variation (n = 12) of the PAPS- dependent DNA binding of 12-OH- and 7,12-diOH-DMBAs also correlated well with DHEA-sulfotransferase activity (r = 0.90; P < 0.00001 and r = 0.92; P < 0.00001, respectively). This sulfation-dependent metabolic activation was not detected in cytosols from human colon, pancreas, larynx or mammary gland. Both TS- and TL-phenol sulfotransferases were active in human liver and colon but only liver contained DHEA- sulfotransferase activity. These results indicate that the sulfotransferase-mediated activation of the methyl-hydroxylated DMBAs is predominantly catalyzed by DHEA-steroid sulfotransferase in human liver and that TS- and TL-phenol sulfotransferases and estrogen sulfotransferase are not involved in the catalysis.   相似文献   
75.
BACKGROUNDCOVID-19 convalescent plasma (CCP) has been considered a treatment option for COVID-19. This trial assessed the efficacy of a neutralizing antibody containing high-dose CCP in hospitalized adults with COVID-19 requiring respiratory support or intensive care treatment.METHODSPatients (n = 105) were randomized 1:1 to either receive standard treatment and 3 units of CCP or standard treatment alone. Control group patients with progress on day 14 could cross over to the CCP group. The primary outcome was a dichotomous composite outcome of survival and no longer fulfilling criteria for severe COVID-19 on day 21.ResultsThe primary outcome occurred in 43.4% of patients in the CCP group and 32.7% in the control group (P = 0.32). The median time to clinical improvement was 26 days in the CCP group and 66 days in the control group (P = 0.27). The median time to discharge from the hospital was 31 days in the CCP group and 51 days in the control group (P = 0.24). In the subgroup that received a higher cumulative amount of neutralizing antibodies, the primary outcome occurred in 56.0% of the patients (vs. 32.1%), with significantly shorter intervals to clinical improvement (20 vs. 66 days, P < 0.05) and to hospital discharge (21 vs. 51 days, P = 0.03) and better survival (day-60 probability of survival 91.6% vs. 68.1%, P = 0.02) in comparison with the control group.ConclusionCCP added to standard treatment was not associated with a significant improvement in the primary and secondary outcomes. A predefined subgroup analysis showed a significant benefit of CCP among patients who received a larger amount of neutralizing antibodies.Trial registrationClinicalTrials.gov NCT04433910.FundingBundesministerium für Gesundheit (German Federal Ministry of Health): ZMVI1-2520COR802.  相似文献   
76.
77.
78.
Background : A retrospective assessment of contrast enhanced computed tomography (CECT) scan findings in histopathologically proven cases of carcinoma of the gallbladder (GB) was performed to review its role in diagnosis, staging and assessment of surgical resectability.  相似文献   
79.
80.
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