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   1291752篇
  免费   89439篇
  国内免费   1566篇
耳鼻咽喉   16597篇
儿科学   41558篇
妇产科学   35382篇
基础医学   191670篇
口腔科学   35110篇
临床医学   120530篇
内科学   251690篇
皮肤病学   27566篇
神经病学   103763篇
特种医学   47565篇
外国民族医学   268篇
外科学   181300篇
综合类   26220篇
现状与发展   3篇
一般理论   577篇
预防医学   106728篇
眼科学   28697篇
药学   94307篇
  39篇
中国医学   2040篇
肿瘤学   71147篇
  2019年   10698篇
  2018年   13897篇
  2017年   10642篇
  2016年   11645篇
  2015年   13376篇
  2014年   18415篇
  2013年   28078篇
  2012年   38383篇
  2011年   40856篇
  2010年   23561篇
  2009年   22654篇
  2008年   38528篇
  2007年   41228篇
  2006年   40844篇
  2005年   39924篇
  2004年   38355篇
  2003年   36683篇
  2002年   35547篇
  2001年   56560篇
  2000年   57589篇
  1999年   48599篇
  1998年   13629篇
  1997年   12409篇
  1996年   12821篇
  1995年   12103篇
  1994年   11277篇
  1993年   10566篇
  1992年   38612篇
  1991年   38062篇
  1990年   36813篇
  1989年   35643篇
  1988年   33037篇
  1987年   32340篇
  1986年   30853篇
  1985年   29096篇
  1984年   22201篇
  1983年   19406篇
  1982年   11523篇
  1979年   21150篇
  1978年   15568篇
  1977年   12946篇
  1976年   11976篇
  1975年   12922篇
  1974年   15747篇
  1973年   15514篇
  1972年   14641篇
  1971年   13679篇
  1970年   12901篇
  1969年   12186篇
  1968年   11326篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Modulation of reactive oxygen and nitrogen species in a tumor could be exploited for nanotherapeutic benefits. We investigate the antitumor effect in Walker-256 carcinosarcoma of magnetic nanodots composed of doxorubicin-loaded Fe3O4 nanoparticles combined with electromagnetic fields. Treatment using the magnetic nanodot with the largest hysteresis loop area (3402 erg/g) had the greatest antitumor effect with the minimum growth factor 0.49 ± 0.02 day–1 (compared to 0.58 ± 0.02 day–1 for conventional doxorubicin). Electron spin resonance spectra of Walker-256 carcinosarcoma treated with the nanodots, indicate an increase of 2.7 times of free iron (that promotes the formation of highly reactive oxygen species), using the nanodot with the largest hysteresis loop area, compared to conventional doxorubicin treatment as well as increases in ubisemiquinone, lactoferrin, NO-FeS-proteins. Hence, we provide evidence that the designed magnetic nanodots can modulate the tumor redox state. We discuss the implications of these results for cancer nanotherapy.  相似文献   
82.
83.
84.
85.
T cell replete HLA-mismatched haploidentical transplantation (HIDT) with post-transplant cyclophosphamide is increasingly becoming an acceptable treatment approach for patients lacking timely access to a suitably matched related donor transplant (MRDT) or matched unrelated donor transplant (MUDT). Multiple recent registry and single-center studies have shown comparable overall survival (OS) and disease-free survival (DFS) rates among HIDT, MRDT, and MUDT with a significantly lower risk of acute and chronic graft-versus-host disease (GVHD) among HIDT recipients. Candidates for allogeneic hematopoietic stem cell transplantation (HSCT) often have access to multiple donor sources, and a relevant question is whether outcomes can be improved with a younger HLA-mismatched haploidentical donor (≤35 years) rather than an older matched related donor (≥35 years) or matched unrelated donor (≥35 years). We analyzed 406 consecutive allogenic HSCT recipients, with a median age of 54 years (range, 19 to 77), after a MRDT with a donor age of ≥35 years (n = 222), MUDT with a donor age of ≥35 years (n = 91), and HIDT with a donor age of ≤35 years (n = 93). Median follow-up time for survivors was 51.5 months. Compared with MRDT and MUDT, HIDT recipients had a similar median age at time of HSCT, hematopoietic cell transplant comorbidity index, disease risk index distribution, and donor recipient sex matching. The survival estimates and relapse incidence at 3 years post-HSCT were OS (64% for MRDT, 54% for MUDT, and 62% for HIDT), DFS (55% for MRDT, 44% for MUDT, and 58% for HIDT), Transplant related mortality (TRM) (19% for MRDT, 16% for MUDT, and 18% for HIDT), and relapse (26% for MRDT, 37% for MUDT, and 24% for HIDT). HIDT recipients had better 3-year relapse rates compared with MUDT recipients (24% versus 37%, P= .048), with similar DFS and OS in a univariate analysis. MRDT recipients had a better relapse rate (26% versus 37%, P = .042) compared with MUDT recipients. Recipients of HIDT also had significantly lower rates of moderate to severe chronic GVHD compared with MRDT and MUDT recipients (P = .01). Multivariable analysis showed no effect of donor on OS, DFS, relapse, and TRM. Recipients of HIDT from a young donor ≤35 years had similar OS, lower rates of chronic GVHD, and better chronic GVHD-free, relapse-free survival compared with patients undergoing transplantation with an MRD or a MUD donor ≥35 years. This study suggests that given a situation where a choice between a young haploidentical relative and an older matched unrelated donor is to be made, one can achieve similar survival with a haploidentical donor and significantly lower rates of chronic GVHD.  相似文献   
86.
87.
ObjectivesThe rise in carbapenem resistance among Gram-negative bacteria has renewed interest in colistin. Recently, the EUCAST-CLSI Polymyxin Breakpoints Working Group declared that broth microdilution (BMD) is the only valid method for colistin susceptibility testing. BMD is not easily incorporated into the routine work of clinical laboratories, and usually this test is incorporated serially, resulting in delayed susceptibility reporting. We tested a strategy of combining VITEK® 2 with a 2 μg/mL colistin agar dilution (VITEK® 2/AD) screening plate to improve performance and time to reporting of colistin susceptibility.MethodsColistin susceptibility for 364 clinical isolates was determined by VITEK® 2/AD and compared with the reference standard BMD according to the ISO 20776-1:2007 and CLSI guidelines. The EUCAST colistin susceptibility breakpoint of ≤2 μg/mL was used. Escherichia coli NCTC 13846 served as quality control strain. Agreement, very major error (VME) and major error rates were determined using ISO 20776-2:2007.ResultsThe VME rate for VITEK® 2 alone was 30.6% (15/49, 95% CI 18.3–45.4%), and was reduced to 10.2% (5/49, 95% CI 3.4–22.2%) using the VITEK® 2/AD combined testing. The combined testing had categorical agreement with BMD of 97% (354/364, 95% CI 95.0–98.7%), and a major error (ME) rate of 1.6% (5/315, 95% CI 0.5–3.7%). Using the combined testing, even against challenging strains, 349 (95.8%, 95% CI 93.3–97.7%) colistin susceptibility results could be reported, and only 15 isolates required further analysis by BMD.DiscussionOur method is simple to apply and allows rapid reporting of colistin susceptibility.  相似文献   
88.
Archives of Women's Mental Health - Latinas in the USA and Spanish-speaking countries experience elevated rates of perinatal depression (PND) because of high psychosocial stressors. Latinas are...  相似文献   
89.
Journal of Artificial Organs - A frequent complication of left ventricular assist devices (LVAD) is the LVAD-associated infections (LVADIs). Contamination may occur during initial surgery/admission...  相似文献   
90.
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