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   14268篇
  免费   686篇
  国内免费   81篇
耳鼻咽喉   191篇
儿科学   216篇
妇产科学   178篇
基础医学   1752篇
口腔科学   422篇
临床医学   840篇
内科学   3827篇
皮肤病学   157篇
神经病学   1078篇
特种医学   558篇
外科学   2583篇
综合类   38篇
一般理论   1篇
预防医学   375篇
眼科学   204篇
药学   814篇
中国医学   27篇
肿瘤学   1774篇
  2023年   91篇
  2022年   238篇
  2021年   373篇
  2020年   194篇
  2019年   269篇
  2018年   308篇
  2017年   266篇
  2016年   318篇
  2015年   317篇
  2014年   407篇
  2013年   499篇
  2012年   865篇
  2011年   962篇
  2010年   580篇
  2009年   457篇
  2008年   811篇
  2007年   873篇
  2006年   844篇
  2005年   822篇
  2004年   784篇
  2003年   735篇
  2002年   748篇
  2001年   275篇
  2000年   297篇
  1999年   258篇
  1998年   151篇
  1997年   126篇
  1996年   91篇
  1995年   103篇
  1994年   88篇
  1993年   87篇
  1992年   189篇
  1991年   197篇
  1990年   180篇
  1989年   160篇
  1988年   140篇
  1987年   108篇
  1986年   127篇
  1985年   100篇
  1984年   60篇
  1983年   60篇
  1982年   41篇
  1981年   30篇
  1980年   27篇
  1979年   60篇
  1978年   25篇
  1977年   41篇
  1970年   30篇
  1969年   27篇
  1968年   23篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
Clinical and Experimental Nephrology - The association between N-terminal pro-brain natriuretic peptide (NT-proBNP) and stroke in Japanese hemodialysis (HD) outpatients is unclear. Therefore, in...  相似文献   
7.
8.
Background and Aims:  The aim of this study was to determine which mouse strains exhibit tolerance to cooling when fertilized oocytes have been stored at 4°C.
Methods:  In-vitro -fertilization-derived oocytes of eight mouse strains were incubated at 4°C in 20 mmol/L Hepes-potassium modified simplex optimized medium (KSOM) medium for 0, 24, 48, 60 or 72 h, and then returned to normal culture conditions at 37°C in KSOM medium. The rates of development of cultured oocytes into blastocysts and cell numbers of blastocysts were examined. In some cases, a Comet assay was carried out to evaluate DNA damage. In addition, the effects of β-mercaptoethanol on the development of the 4°C-treated oocytes were assessed.
Results:  Of the eight strains tested, BDF1, B6C3F1 and FVB/N strains exhibited relatively higher degrees of tolerance to 4°C treatment and approximately 90%, 83% and 78% of oocytes treated at 4°C for 48 h developed to morphologically normal blastocysts, respectively. Comet assay revealed no clear DNA damage in oocytes treated at 4°C. Treatment with β-mercaptoethanol failed to improve the in vitro survival rate of low-temperature-treated oocytes.
Conclusion:  Strain differences were observed in tolerance to cooling treatment when fertilized oocytes were temporarily treated with 4°C, although the reasons for this remain unclear. (Reprod Med Biol 2006; 5 : 43–50)  相似文献   
9.
Anthocyanins, which are responsible for a variety of bright colors (including red, blue, and purple) in fruits, vegetables, and flowers, are consumed as dietary polyphenols. Anthocyanin-containing fruits are thought to decrease coronary heart disease and are used in anti-diabetic preparations. Diabetes is associated with a variety of cardiovascular complications that may be mediated by endothelial dysfunction, and so this study was designed mainly to characterize the influence of a synthesized anthocyanidin derivative (HK-008) over acetylcholine (ACh)-induced relaxation in mesenteric arterial beds isolated from rats. In a glucose-tolerance test in intact rats, HK-008 (30 mg/kg) reduced the glucose level as effectively as the same dose of glibenclamide. The aortic relaxation induced by pinacidil (an ATP-sensitive potassium channel opener) was greatly inhibited by glibenclamide (10 microM), and also significantly inhibited by HK-008 (10 microM). Interestingly, the ACh-induced relaxation in the perfused, preconstricted mesenteric arterial bed was significantly enhanced by HK-008 (10 microM), and this enhancement was significantly attenuated by indomethacin (10 microM). The ACh-induced mesenteric relaxation was impaired by an increase in oxidative stress, viz. superoxide-generating treatment [xanthine oxidase (XO; 0.1 U/ml) plus hypoxanthine (HX; 10 microM)]. However, this impairment was strongly suppressed by HK-008 (10 microM). These results suggest that HK-008 increases endothelium-induced relaxation by suppressing oxidative stress or modulating prostanoids signaling. This compound may therefore be useful against certain cardiovascular disorders.  相似文献   
10.
Abstract: The adsorptive characteristics of 5 dialysis membranes for recombinant human erythropoietin (EPO) were studied in vitro in a closed circuit system. For 120 min, EPO added with bovine serum was significantly adsorbed by polymethylmetacrylate (PMMA) and polyacry–lonitrile (PAN) membranes but not by Cuprophan, ethylene vinyl alcohol (EVAL), or polysulfone (PS) membranes. In addition the EPO adsorptive rate, as well as that of β2–microglobulin (β2–MG), was greater with a PMMA membrane than with a PAN membrane. EPO was not detected in the ultrafiltrate at 15 min with 5 membranes. These results indicate that EPO was eliminated by membrane adsorption only with some dialysis membranes.  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