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   507篇
  免费   26篇
  国内免费   2篇
耳鼻咽喉   1篇
儿科学   39篇
妇产科学   20篇
基础医学   56篇
口腔科学   15篇
临床医学   45篇
内科学   86篇
皮肤病学   14篇
神经病学   23篇
特种医学   36篇
外科学   51篇
综合类   22篇
预防医学   22篇
眼科学   18篇
药学   53篇
中国医学   1篇
肿瘤学   33篇
  2023年   3篇
  2022年   7篇
  2021年   11篇
  2020年   5篇
  2019年   5篇
  2018年   11篇
  2017年   14篇
  2016年   14篇
  2015年   17篇
  2014年   24篇
  2013年   26篇
  2012年   25篇
  2011年   20篇
  2010年   15篇
  2009年   22篇
  2008年   21篇
  2007年   18篇
  2006年   24篇
  2005年   22篇
  2004年   28篇
  2003年   23篇
  2002年   12篇
  2001年   14篇
  2000年   7篇
  1999年   9篇
  1998年   15篇
  1997年   10篇
  1996年   10篇
  1995年   4篇
  1994年   7篇
  1993年   6篇
  1992年   5篇
  1990年   7篇
  1989年   6篇
  1988年   3篇
  1987年   8篇
  1986年   4篇
  1985年   4篇
  1984年   5篇
  1983年   7篇
  1981年   3篇
  1980年   4篇
  1977年   3篇
  1976年   3篇
  1975年   2篇
  1974年   2篇
  1973年   3篇
  1971年   2篇
  1967年   2篇
  1966年   2篇
排序方式: 共有535条查询结果,搜索用时 0 毫秒
41.
42.
43.
Human cytosolic sulfotransferases (SULTs) catalyze the sulfate conjugation of several important endo- and xenobiotics. Among the superfamily of SULT enzymes, SULT1A1 catalyzes the sulfation of small planar phenolic compounds, whereas SULT1E1 has a major role in estrogen conjugation. The human SULT1A1 gene has common single nucleotide polymorphisms that define three allozymes, SULT1A1*1, *2, and *3. The enzyme kinetics of SULT1A1 allozymes and SULT1E1 were characterized for the polyphenolic substrates apigenin, chrysin, epicatechin, quercetin, and resveratrol. Purified recombinant SULT proteins were generated in a baculoviral-insect cell system, and incubated in vitro with each substrate to determine catalytic activity. The effect of polyphenol sulfation was examined in mammalian cell lines stably expressing SULT1E1. For all polyphenols investigated, "normal-activity" SULT1A1*1 allozyme had significantly greater Vmax estimates than SULT1E1, and allele-specific differences in SULT1A1-mediated sulfation were observed. The polymorphic SULT1A1*2 allozyme exhibited low activity toward apigenin, epicatechin, and resveratrol. SULT1A1*1 and *3 acted as normal-activity allozymes for these substrates. Altered cellular proliferation was observed in MCF-7 cells stably expressing SULT1E1 upon treatment with chrysin, quercetin, or resveratrol, thus suggesting inactivation of these compounds by SULT1E1. These results suggest an important role for SULT isozymes and their pharmacogenetics in polyphenol disposition.  相似文献   
44.
45.
46.
BACKGROUNDIn monotherapy studies for bleeding peptic ulcers, large volumes of epinephrine were associated with a reduction in rebleeding. However, the impact of epinephrine volume in patients treated with combination endoscopic therapy remains unclear. AIMTo assess whether epinephrine volume was associated with bleeding outcomes in individuals who also received endoscopic thermal therapy and/or clipping.METHODSData from 132 patients with Forrest class Ia, Ib, and IIa peptic ulcers were reviewed. The primary outcome was further bleeding at 7 d; secondary outcomes included further bleeding at 30 d, need for additional therapeutic interventions, post-endoscopy blood transfusions, and 30-day mortality. Logistic and linear regression and Cox proportional hazards analyses were performed.RESULTSThere was no association between epinephrine volume and all primary and secondary outcomes in multivariable analyses. Increased odds for further bleeding at 7 d occurred in patients with elevated creatinine values (aOR 1.96, 95%CI 1.30-3.20; P < 0.01) or hypotension requiring vasopressors (aOR 6.34, 95%CI 1.87-25.52; P < 0.01). Both factors were also associated with all secondary outcomes.CONCLUSIONEpinephrine maintains an important role in the management of bleeding ulcers, but large volumes up to a range of 10-20 mL are not associated with improved bleeding outcomes among individuals receiving combination endoscopic therapy. Further bleeding is primarily associated with patient factors that likely cannot be overcome by increased volumes of epinephrine. However, in carefully-selected cases where ulcer location or size pose therapeutic challenges or when additional modalities are unavailable, it is conceivable that increased volumes of epinephrine may still be beneficial.  相似文献   
47.
The aim of this study was to evaluate the association between dental status and the prevalence and severity of osseous changes in the temporomandibular joints of human skulls from the Roman–Byzantine period. Fifty‐eight skulls from 36 men and 22 women between the ages of 19 and 63 years were studied, and the following parameters were evaluated: morphological osseous changes in the articular surface of the condyles, tooth wear and molar support. A significant correlation between age and dental wear or loss of molar support was observed, although no correlation was noted between age and morphological osseous changes in the condyles. The loss of molar support was significantly correlated with morphological osseous changes of the condyles, whereas no significant correlation was found between dental wear and condylar changes. This study demonstrates that the loss of molar support can serve as a predictor of osseous changes in the condyle. Reduced molar support may be one of the aetiologies associated with morphological osseous changes in temporomandibular joints. Further studies should to be performed to investigate this potential correlation.  相似文献   
48.
Cathepsin K (CK), a lysosomal cysteine protease, is highly expressed in mature osteoclasts and degrades type 1 collagen. Odanacatib (ODN) is a selective and reversible CK inhibitor that inhibits bone loss in preclinical and clinical studies. Although an antiresorptive, ODN does not suppress bone formation, which led us to hypothesize that ODN may display restorative effect on the osteopenic bones. In a curative study, skeletally mature New Zealand rabbits were ovarectomized (OVX) and after induction of bone loss were given a steady‐state exposure of ODN (9 mM/d) for 14 weeks. Sham‐operated and OVX rabbits treated with alendronate (ALD), 17b‐estradiol (E2), or parathyroid hormone (PTH) served as various controls. Efficacy was evaluated by assessing bone mineral density (BMD), bone microarchitecture (using micro‐computed tomography), fluorescent labeling of bone, and biomechanical strength. Skeletal Ca/P ratio was measured by scanning electron microscopy (SEM) with X‐ray microanalysis, crystallinity by X‐ray diffraction, and bone mineral density distribution (tissue mineralization) by backscattered SEM. Between the sham and ODN‐treated osteopenic groups, lumbar and femur metaphyseal BMD, Ca/P ratio, trabecular microstructure and geometric indices, vertebral compressive strength, trabecular lining cells, cortical parameters (femoral area and thickness and periosteal deposition), and serum P1NP were largely comparable. Skeletal improvements in ALD‐treated or E2‐treated groups fell significantly short of the sham/ODN/PTH group. However, the ODN group displayed reduced ductility and enhanced brittleness of central femur, which might have been contributed by higher crytallinity and tissue mineralization. Rabbit bone marrow stromal cells expressed CK and when treated with ODN displayed increased formation of mineralized nodules and decreased apoptosis in serum‐deficient medium compared with control. In vivo, ODN did not suppress remodeling but inhibited osteoclast activity more than ALD. Taken together, we show that ODN reverses BMD, skeletal architecture, and compressive strength in osteopenic rabbits; however, it increases crystallinity and tissue mineralization, thus leading to increased cortical bone brittleness. © 2015 American Society for Bone and Mineral Research.  相似文献   
49.
Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - The use of herbs in the form of dietary supplements and medicine is fascinating the world, owing to their...  相似文献   
50.
Immunological diseases of the hepatobiliary system and the pancreas include a broad spectrum of disorders that manifest characteristic histopathology/serology and variable clinical features and imaging findings. Recent studies have thrown fresh light on the complex role of genetics and autoimmunity in the pathogenesis and natural history of these diverse disorders that include autoimmune hepatitis, primary biliary cirrhosis, primary sclerosing cholangitis, IgG4-related cholangitis, overlap/outlier syndromes, and autoimmune pancreatitis.  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