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   872篇
  免费   111篇
  国内免费   1篇
  2021年   7篇
  2019年   7篇
  2018年   9篇
  2016年   13篇
  2015年   22篇
  2014年   24篇
  2013年   44篇
  2012年   45篇
  2011年   32篇
  2010年   28篇
  2009年   19篇
  2008年   36篇
  2007年   35篇
  2006年   35篇
  2005年   42篇
  2004年   38篇
  2003年   40篇
  2002年   34篇
  2001年   12篇
  2000年   12篇
  1999年   7篇
  1998年   18篇
  1997年   7篇
  1996年   8篇
  1993年   7篇
  1992年   11篇
  1991年   8篇
  1990年   12篇
  1988年   9篇
  1987年   10篇
  1986年   8篇
  1985年   13篇
  1984年   9篇
  1983年   11篇
  1982年   8篇
  1981年   10篇
  1980年   14篇
  1979年   14篇
  1978年   15篇
  1977年   8篇
  1976年   9篇
  1973年   14篇
  1972年   7篇
  1970年   7篇
  1964年   9篇
  1962年   9篇
  1961年   7篇
  1958年   6篇
  1957年   7篇
  1956年   6篇
排序方式: 共有984条查询结果,搜索用时 15 毫秒
61.
62.
63.
In this paper, we describe the development of a novel series of high affinity, orally bioavailable 3-amino-1,4 benzodiazepine-based gamma-secretase inhibitors for the potential treatment of Alzheimer's disease. We disclose structure-activity relationships based around the 1, 3 and 5 positions of the benzodiazepine core structure.  相似文献   
64.
65.
66.
Earlier studies demonstrated that not only thestomach but also the esophageal wall served as an appropriate site forestimating the severity of circulatory shock by using tonometricmethods. We then conceived of the option of sublingual tonometry. Inthe present study, we tested the hypothesis that the changes insublingual PCO2 serve as indicatorsof decreases in blood flow to sublingual and visceraltissue. In Sprague-Dawley rats, sublingual PCO2 increased from 50 to 127 Torrand arterial blood lactate increased from 0.9 to 11.2 mmol/l duringbleeding. Sublingual blood flow simultaneously decreased to ~32% ofpreshock values. After reinfusion of shed blood, organ blood flows andsublingual PCO2 were promptlyrestored to near-baseline values. There were corresponding decreases inblood flows in the tongue, stomach, jejunum, colon, and kidneys duringhemorrhagic shock. Increases in sublingualPCO2 were highly correlated with decreases in sublingual blood flow (r = 0.80), tongue blood flow (r = 0.81),gastric blood flow (r = 0.74), jejunalblood flow (r = 0.65), colon bloodflow (r = 0.80), and renal blood flow (r = 0.75). Unbled control animalsdemonstrated no significant changes. Therefore, we anticipate thatsublingual tonometry will provide a useful, noninvasive alternative formonitoring visceral PCO2.

  相似文献   
67.
Vaccine-induced HIV antibodies were evaluated in serum samples collected from healthy Tanzanian volunteers participating in a phase I/II placebo-controlled double blind trial using multi-clade, multigene HIV-DNA priming and recombinant modified vaccinia Ankara (HIV-MVA) virus boosting (HIVIS03). The HIV-DNA vaccine contained plasmids expressing HIV-1 gp160 subtypes A, B, C, Rev B, Gag A, B and RTmut B, and the recombinant HIV-MVA boost expressed CRF01_AE HIV-1 Env subtype E and Gag-Pol subtype A. While no neutralizing antibodies were detected using pseudoviruses in the TZM-bl cell assay, this prime-boost vaccination induced neutralizing antibodies in 83% of HIVIS03 vaccinees when a peripheral blood mononuclear cell (PBMC) assay using luciferase reporter-infectious molecular clones (LucR-IMC) was employed. The serum neutralizing activity was significantly (but not completely) reduced upon depletion of natural killer (NK) cells from PBMC (p=0.006), indicating a role for antibody-mediated Fcγ-receptor function. High levels of antibody-dependent cellular cytotoxicity (ADCC)-mediating antibodies against CRF01_AE and/or subtype B were subsequently demonstrated in 97% of the sera of vaccinees. The magnitude of ADCC-mediating antibodies against CM235 CRF01_AE IMC-infected cells correlated with neutralizing antibodies against CM235 in the IMC/PBMC assay. In conclusion, HIV-DNA priming, followed by two HIV-MVA boosts elicited potent ADCC responses in a high proportion of Tanzanian vaccinees. Our findings highlight the potential of HIV-DNA prime HIV-MVA boost vaccines for induction of functional antibody responses and suggest this vaccine regimen and ADCC studies as potentially important new avenues in HIV vaccine development.

Trial Registration

Controlled-Trials ISRCTN90053831 The Pan African Clinical Trials Registry ATMR2009040001075080 (currently PACTR2009040001075080)  相似文献   
68.
69.

Background

Several studies have shown that the waist circumference of children and adolescents has increased over the last 25 years. However, given the strong correlation between waist circumference and BMI, it is uncertain if the secular trends in waist circumference are independent of those in BMI.

Methods

We analyzed data from 6- to 19-year-olds who participated in the 1988–1994 through 2011–2012 cycles of the National Health and Nutrition Examination Survey to assess whether the trends in waist circumference were independent of changes in BMI, race-ethnicity and age.

Results

Mean, unadjusted levels of waist circumference increased by 3.7 cm (boys) and 6.0 cm (girls) from 1988–94 through 2011–12, while mean BMI levels increased by 1.1 kg/m2 (boys) and 1.6 kg/m2 (girls). Overall, the proportional changes in mean levels of both waist circumference and BMI were fairly similar among boys (5.3%, waist vs. 5.6%, BMI) and girls (8.7%, waist vs. 7.7%, BMI). As assessed by the area under the curve, adjustment for BMI reduced the secular increases in waist circumference by about 75% (boys) and 50% (girls) beyond that attributable to age and race-ethnicity. There was also a race-ethnicity interaction (p < 0.001). Adjustment for BMI reduced the secular trend in waist circumference among non-Hispanic (NH) black children (boys and girls) to a greater extent (about 90%) than among other children.

Conclusions

Our results indicate that among children in the U.S., about 75% (boys) and 50% (girls) of the secular increases in waist circumference since 1988–94 can be accounted for by changes in BMI. The reasons for the larger independent effects among girls and among NH blacks are uncertain.  相似文献   
70.
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