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   8412篇
  免费   577篇
  国内免费   106篇
  9095篇
  2022年   73篇
  2021年   159篇
  2020年   74篇
  2019年   96篇
  2018年   116篇
  2017年   94篇
  2016年   142篇
  2015年   210篇
  2014年   254篇
  2013年   408篇
  2012年   452篇
  2011年   437篇
  2010年   264篇
  2009年   250篇
  2008年   307篇
  2007年   327篇
  2006年   315篇
  2005年   286篇
  2004年   251篇
  2003年   247篇
  2002年   258篇
  2001年   195篇
  2000年   200篇
  1999年   171篇
  1998年   83篇
  1997年   85篇
  1996年   81篇
  1995年   76篇
  1994年   74篇
  1993年   72篇
  1992年   178篇
  1991年   159篇
  1990年   159篇
  1989年   145篇
  1988年   125篇
  1987年   145篇
  1986年   123篇
  1985年   158篇
  1984年   147篇
  1983年   146篇
  1982年   111篇
  1981年   92篇
  1979年   136篇
  1978年   96篇
  1977年   100篇
  1976年   76篇
  1975年   90篇
  1974年   91篇
  1973年   85篇
  1972年   96篇
排序方式: 共有9095条查询结果,搜索用时 15 毫秒
91.
Androgen receptor predominance in human ovarian carcinoma   总被引:2,自引:0,他引:2  
Cytosols of 94 untreated common epithelial ovarian cancer tissues were analysed for the presence of estrogen-, progesterone- and androgen receptors. Androgen receptors clearly predominated (90%) over and above estrogen- (55%) and progesterone receptors (52%). Further characterisation particularly of the androgen receptor revealed steroid-receptor complex with the sedimentation coefficient similar to ovalbumin (3,6 S). Only androgens, natural and synthetic, were able to alter the sedimentation profile. Estrogen appeared to slightly lower the peak, while progesterone and cortisol did not alter the profile at all. No difference in receptor concentrations between tumor tissues from pre-, peri- and postmenopausal women was found. The serum hormone levels (estradiol-17 beta, testosterone, FSH, LH) measured preoperatively in 20 postmenopausal patients did not correlate with the receptor status. Majority of the ovarian carcinomas studied contained androgen receptors. We therefore suggest consideration of the addition of anti-androgens to the therapeutic strategies applicable to ovarian cancer.  相似文献   
92.
A nonlinear mathematical model which incorporates both beta-cell kinetics and a glucose-insulin feedback system is proposed for describing the time variations of plasma glucose and insulin levels. Numerical simulations show that this model is consistent with experimental observations on normal groups. An analysis of the changes in the solutions with variations in the parameters showed that a decrease in a single parameter gave results consistent with experimental findings in protein-deficient (malnutrition-related) diabetes mellitus (PDDM). The model predicts that it is the function and not the number of beta cells which is reduced in PDDM.  相似文献   
93.
94.
In vivo fluorescence imaging uses a sensitive camera to detect fluorescence emission from fluorophores in whole-body living small animals. To overcome the photon attenuation in living tissue, fluorophores with long emission at the near-infrared (NIR) region are generally preferred, including widely used small indocarbocyanine dyes. The list of NIR probes continues to grow with the recent addition of fluorescent organic, inorganic and biological nanoparticles. Recent advances in imaging strategies and reporter techniques for in vivo fluorescence imaging include novel approaches to improve the specificity and affinity of the probes and to modulate and amplify the signal at target sites for enhanced sensitivity. Further emerging developments are aiming to achieve high-resolution, multimodality and lifetime-based in vivo fluorescence imaging.  相似文献   
95.
96.
97.
Rare earth ions (Eu3+ or Tb3+)‐activated Ca3 Ga2 Si3O12 (CaGaSi) phosphors were synthesized by using a sol–gel method. Photoluminescence spectra of Eu3+:CaGaSi phosphors exhibited five emission bands at 578, 592, 612, 652 and 701 nm, which were assigned to the transitions (5D07F0, 7F1, 7F2, 7F3 and 7F4), respectively, with an excitation wavelength of λexci = 392 nm. Among these, the transition 5D07F2 (612 nm) displayed bright red emission. In the case of Tb3+:CaGaSi phosphors, four emission bands were observed at 488 (5D47F6), 543 (5D47F5), 584 (5D47F4) and 614 nm (5D47F3) from the measurement of PL spectra with λexci = 376 nm. Among these, the transition 5D47F5 at 543 nm displayed bright green emission. The structure and morphology of the phosphors were studied from the measurements of X‐ray diffraction (XRD), scanning electron microscopy (SEM) and energy‐dispersive X‐ray analysis (EDAX) results. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   
98.
Waardenburg syndrome (WS) is a dominantly inherited and clinically variable syndrome of deafness, pigmentary changes, and distinctive facial features. Clinically, WS type I (WS1) is differentiated from WS type II (WS2) by the high frequency of dystopia canthorum in the family. In some families, WS is caused by mutations in the PAX3 gene on chromosome 2q. We have typed microsatellite markers within and flanking PAX3 in 41 WS1 kindreds and 26 WS2 kindreds in order to estimate the proportion of families with probable mutations in PAX3 and to study the relationship between phenotypic and genotypic heterogeneity. Evaluation of heterogeneity in location scores obtained by multilocus analysis indicated that WS is linked to PAX3 in 60% of all WS families and in 100% of WS1 families. None of the WS2 families were linked. In those families in which equivocal lod scores (between −2 and +1) were found, PAX3 mutations have been identified in 5 of the 15 WS1 families but in none of the 4 WS2 families. Although preliminary studies do not suggest any association between the phenotype and the molecular pathology in 20 families with known PAX3 mutations and in four patients with chromosomal abnormalities in the vicinity of PAX3, the presence of dystopia in multiple family members is a reliable indicator for identifying families likely to have a defect in PAX3.  相似文献   
99.
100.
A series of 1-substituted-3-(6-methylpyridin-2-yl)-4-([1,2,4]triazolo[1,5-a]pyridin-6-yl)pyrazoles 14a-ae, 16a, 16b, and 21a-c has been prepared and evaluated for their ALK5 inhibitory activity in an enzyme assay and in a cell-based luciferase reporter assay. The 4-([1,2,4]triazolo[1,5-a]pyridin-6-yl)-N-(4-methoxyphenyl)-3-(6-methylpyridin-2-yl)-1H-pyrazole-1-carbothioamide (14n) inhibited ALK5 phosphorylation with IC(50) value of 0.57 nM and showed 94% inhibition at 100 nM in a luciferase reporter assay using HaCaT cells permanently transfected with p3TP-luc reporter construct.  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