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   2763篇
  免费   256篇
  国内免费   3篇
耳鼻咽喉   67篇
儿科学   154篇
妇产科学   41篇
基础医学   469篇
口腔科学   38篇
临床医学   348篇
内科学   599篇
皮肤病学   43篇
神经病学   236篇
特种医学   202篇
外国民族医学   1篇
外科学   289篇
综合类   57篇
预防医学   178篇
眼科学   30篇
药学   168篇
中国医学   1篇
肿瘤学   101篇
  2023年   12篇
  2022年   14篇
  2021年   45篇
  2020年   23篇
  2019年   50篇
  2018年   59篇
  2017年   40篇
  2016年   35篇
  2015年   49篇
  2014年   85篇
  2013年   123篇
  2012年   121篇
  2011年   125篇
  2010年   95篇
  2009年   98篇
  2008年   131篇
  2007年   142篇
  2006年   159篇
  2005年   138篇
  2004年   99篇
  2003年   96篇
  2002年   95篇
  2001年   81篇
  2000年   58篇
  1999年   56篇
  1998年   45篇
  1997年   63篇
  1996年   55篇
  1995年   47篇
  1994年   47篇
  1993年   41篇
  1992年   53篇
  1991年   34篇
  1990年   32篇
  1989年   66篇
  1988年   50篇
  1987年   58篇
  1986年   44篇
  1985年   50篇
  1984年   43篇
  1983年   24篇
  1982年   16篇
  1981年   21篇
  1980年   24篇
  1979年   23篇
  1978年   17篇
  1977年   24篇
  1974年   15篇
  1971年   10篇
  1969年   10篇
排序方式: 共有3022条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
Nephrotoxic cysteine conjugates derived from a variety of halogenated alkenes are enzymatically activated via the beta-lyase pathway to yield reactive sulfur-containing metabolites which bind covalently to cellular macromolecules. Mitochondria contain beta-lyase enzymes and are primary targets for binding and toxicity. Previously, mitochondrial protein and/or DNA have been considered as molecular targets for cysteine conjugate metabolite binding. We now report that metabolites of nephrotoxic cysteine conjugates form covalent adducts with rat kidney mitochondrial phospholipids. Rat kidney mitochondria were incubated with the 35S-labeled conjugates S-(1,1,2,2-tetrafluoroethyl)-L-cysteine (TFEC), S-(2-chloro-1,1,2-trifluoroethyl)-L-cysteine (CTFC), S-(1,2-dichlorovinyl)-L-cysteine, and S-(1,2,3,4,4-pentachlorobutadienyl)-L-cysteine. Quantitation of metabolite binding to whole mitochondria and to mitochondrial protein and lipid fractions revealed that as much as 42% of the 35S-label associated with the mitochondria was found in the lipid fraction. Total lipids were also extracted from 35S-treated mitochondria and separated by thin-layer chromatography. 35S-Containing metabolites were found in the lipid fractions from mitochondria treated with each of the conjugates. Lipids from both [35S]CTFC- and [35S]-TFEC-treated mitochondria contained major 35S-labeled lipid adducts which had similar mobility by thin-layer chromatography. Fatty acid analysis, 19F and 31P NMR spectroscopy, and mass spectrometric analyses confirmed that the major TFEC and CTFC adducts are thioamides of phosphatidylethanolamine.  相似文献   
7.
8.
AD  Giannoukas  N  Labropoulos  FCT  Smith  GS  Venables  JD  Beard  武婕 《中华脑血管病论坛》2005,3(5):555-560
目的由于卒中风险随着狭窄严重程度的增加而升高,因此认为颈内动脉(ICA)接近闭塞患者的卒中风险很高。在现有的随机试验中,还没有专门针对这种情况进行探讨,因此其处理尚存在争汶。方法:对相关文献进行系统评价。结果:对ICA接近闭塞患者的处理还存在争议:一些学者支持进行干预,而另一些学者则认为存在风险或没有益处而反对进行干预。在ICA接近闭塞的有症状患者中进行一项比较外科治疗与最佳内科治疗的多中心前瞻性随机试验似乎非常困难,因为这类研究需要大量的患者。尽管如此,基于目前的证据,似乎很难拒绝手术治疗。结论:由于目前对ICA接近闭塞患者的最佳处理方案仍存在着争议,因此需要前瞻性观察性研究以证实其在有症状和无症状人群中的患病率以及相关的卒中风险。基于目前的证据,大多数医疗中心选择手术治疗,但它相对干内科治疗的特粱尚右待证章.  相似文献   
9.
10.
OBJECTIVE: Transmission of Staphylococcus aureus via air may play an important role in healthcare settings. This study investigates the impact of barrier precautions on the spread of airborne S. aureus by volunteers with experimentally induced rhinovirus infection (ie, the common cold). DESIGN: Prospective nonrandomized study. SETTING: Wake Forest University School of Medicine (Winston-Salem, NC).Participants. A convenience sample of 10 individuals with nasal S. aureus carriage selected from 593 students screened for carriage. INTERVENTION: Airborne S. aureus dispersal was studied in the 10 participants under the following clothing conditions: street clothes, surgical scrubs, surgical scrubs and a gown, and the latter plus a face mask. After a 4-day baseline period, volunteers were exposed to a rhinovirus, and their clinical course was followed for 12 days. Daily swabs of nasal specimens, pharynx specimens, and skin specimens were obtained for quantitative culture, and cold symptoms were documented. Data were analyzed by random-effects negative binomial models. RESULTS: All participants developed a common cold. Incidence rate ratios (IRRs) indicated that, compared with airborne levels of S. aureus during sessions in which street clothes were worn, airborne levels decreased by 75% when surgical scrubs were worn (P<.001), by 80% when scrubs and a surgical gown were worn (P<.001), and by 82% when scrubs, a gown, and a face mask were worn (P<.001). The addition of a mask to the surgical scrubs and gown did not reduce the airborne dispersal significantly (IRR, 0.92; P>.05). Male volunteers shed twice as much S. aureus as females (incidence rate ratio, 2.04; P=.013). The cold did not alter the efficacy of the barrier precautions. CONCLUSIONS: Scrubs reduced the spread of airborne S. aureus, independent of the presence of a rhinovirus-induced cold. Airborne dispersal of S. aureus during sessions in which participants wore surgical scrubs was not significantly different from that during sessions in which gowns and gowns plus masks were also worn.  相似文献   
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