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   678篇
  免费   68篇
  国内免费   1篇
耳鼻咽喉   2篇
儿科学   29篇
妇产科学   16篇
基础医学   60篇
口腔科学   11篇
临床医学   76篇
内科学   197篇
皮肤病学   14篇
神经病学   55篇
特种医学   41篇
外科学   87篇
综合类   8篇
一般理论   1篇
预防医学   57篇
眼科学   12篇
药学   45篇
中国医学   8篇
肿瘤学   28篇
  2023年   5篇
  2022年   15篇
  2021年   19篇
  2020年   14篇
  2019年   21篇
  2018年   27篇
  2017年   13篇
  2016年   11篇
  2015年   10篇
  2014年   34篇
  2013年   28篇
  2012年   44篇
  2011年   35篇
  2010年   30篇
  2009年   18篇
  2008年   35篇
  2007年   36篇
  2006年   29篇
  2005年   36篇
  2004年   18篇
  2003年   18篇
  2002年   20篇
  2001年   19篇
  2000年   14篇
  1999年   9篇
  1998年   10篇
  1997年   6篇
  1996年   7篇
  1995年   5篇
  1992年   5篇
  1991年   5篇
  1990年   6篇
  1989年   7篇
  1988年   7篇
  1987年   7篇
  1986年   15篇
  1985年   12篇
  1984年   6篇
  1983年   8篇
  1982年   12篇
  1981年   9篇
  1980年   6篇
  1979年   10篇
  1978年   5篇
  1977年   7篇
  1975年   7篇
  1974年   5篇
  1973年   3篇
  1972年   3篇
  1971年   4篇
排序方式: 共有747条查询结果,搜索用时 31 毫秒
101.
A more aesthetic correction of a meatal stricture that avoids the hypospadiac appearance of the glans after conventional meatoplasty procedures is presented.  相似文献   
102.
Clinical neurological findings in 47 children with lumbosacral myelodysplasia did not correlate well with the existing dysfunction of the lower urinary tract as diagnosed by urodynamic studies. The level of intact skin sensation, and the presence or absence of bulbocavernosus and anal reflexes could not significantly predict the function of the detrusor muscle, proximal urethra and striated urethral sphincter. Therefore, one should not rely on a clinical neurological examination to outline the urological management in such patients.  相似文献   
103.
104.
Protracted yet variable major pulmonary artery compression in sarcoidosis.   总被引:1,自引:0,他引:1  
H F Faunce  G C Ramsay  W Sy 《Radiology》1976,119(2):313-314
A case of thoracic sarcoidosis showing diffuse mediastinal lymphadenopathy was followed for a 6-month period with serial chest radiographs, perfusion lung scans, and pulmonary angiograms. Significant extrinsic pressure upon major pulmonary arteries from large lymph nodes of sarcoidosis was seen to cause marked restriction in pulmonary parenchymal perfusion on both scanning and angiography.  相似文献   
105.
106.
107.
A New Elution Procedure Using Chloroform, a Nonflammable Organic Solvent   总被引:2,自引:0,他引:2  
A new method for eluting red cell antibodies using chloroform has been shown to be effective. The method is similar to ether and xylene techniques but can be completed within 10 min after adequate cell washing. Comparison studies using ether, xylene and chloroform showed that antibodies eluted by chloroform yielded equivalent titration scores. Antibodies within the Ss blood group system were easily eluted using chloroform but not using ether. Also, the chloroform method yielded informative eluates when prepared from red cells of patients with warm antibody autoimmune hemolytic anemia, drug-induced immune hemolytic anemia, hemolytic disease of the newborn caused by ABO or Rh fetal-maternal incompatibility, or from patients having a positive direct antiglobulin test as a result of alloantibodies stimulated by recent transfusion ('delayed transfusion reaction'). The advantages of chloroform elution are: (1) chloroform is nonflammable; (2) the eluate is readily obtained from the top layer after centrifugation; (3) no residual solvent remains in the eluate, and (4) the method is rapid.  相似文献   
108.
In this preliminary study, water soluble contrast media (CM) were administrated to normal laboratory rats (n = 11) and renal function was monitored before and followed after this challenge. A significant decrease (p less than or equal to 0.001) of the absolute urinary creatinine output, was noted during 3 days after the injection of the CM: the median (M) control value was 0.0313 mumol/min. 100 g body weight (BW) (interquartile range (IR): 0.0014) while the M values the first, the second and the third day were 0.0209 mumol/min. 100 g BW (IR: 0.0141), 0.0198 mumol/min. 100 g BW (IR: 0.0044) and 0.0265 mumol/min. 100 g BW (IR: 0.0054) respectively. The serum creatinine 24 hours after injection was 59,8 mumol/l (IR: 7.92) which is significantly higher (p less than or equal to 0.002) compared to the M serum creatinine of 51.9 mumol/l (IR: 15.0) evaluated in a group of normal unchallenged laboratory rats. These changes are in contrast with the low frequency of renal failure episodes encountered in clinical circumstances. Further experiments with inclusion of a control group receiving a sham injection seem necessary.  相似文献   
109.
Abstract. 2 patients having α-methyldopa-induced hemolytic anemia were followed sequentially using an in vitro assay of autologous monocyte-macrophage activity to determine if their reticuloendothelial system (RES) function was abnormal and thus could be related to the mechanism of lysis. RES function was evaluated while the patients were actively hemolyzing and during remission, following discontinuance of the drug. The results indicated that RES activity is normal in patients having hemolytic anemia due to a-methyldopa administration. Also, following cessation of drug therapy, the patients' IgG-coated red cells interacted significantly for a prolonged period (4–5 months) with autologous or normal allogeneic monocyte-macrophages. This was associated with a concurrent reti-culocytosis and indicates a persistent low-level hemolytic phase throughout this period, even though hemoglobin and hematocrit values remained within the normal ranges. Although levels of IgG sensitizing the patients' red cells were essentially constant during the hemolytic phase and when the patients were in complete remission, significant monocyte-macrophage activity was only evident during the hemolytic period. In an attempt to explain this phenomenon, it is postulated that hemolysis in patients receiving α-methyldopa is related to the interaction of drug with red cell membrane proteins which results in a variably expressed 'altered' antigen which is recognized by 'autoantibody'. The proper expression of the Fc portion of the immunoglobin molecule to result in specific recognition by receptors on monocyte-macrophages depends upon the extent of the antigen alteration by α-methyldopa. If the drug does not result in appropriate antigen alteration, then, although 'autoantibody' may still bind to the red blood cell, its Fc region is not readily recognized by monocyte-macrophages and little or no erythrophagocytosis occurs.  相似文献   
110.
Plant phenolic compounds isolated from a 70% aqueous acetone extract of the leaves of Malus doumeri A. CHEV. var. formosana (KAWAK. & KOIDZ.) S. S. YING, a type of Taiwanese indigenous plant, were evaluated for potential application in the field of skin care. A phytochemical investigation of the active fractions resulted in the isolation of seven compounds of which the structures were identified by spectroscopic characterization. In the present study, the isolated phenolic compounds were evaluated for their free radical-scavenging activities against 1,1-diphenyl-2-picrylhydrazyl (DPPH) and the superoxide radicals, anti-elastase, and for their anti-matrix metalloproteinase-1 (MMP-1) activity in human skin fibroblast cells. Of these compounds, 3-hydroxyphloridzin (2), 3-hydroxyphloretin (6), and quercetin (7) exhibited the strongest DPPH and superoxide radical-scavenging activities. The IC50 values of these compounds were 9.2, 7.7, and 15.4 microM, respectively, for the DPPH radical, and 25.0, 19.6, and 42.6 microM, respectively, for the superoxide radical. 3-Hydroxyphloridzin (2) and 3-hydroxyphloretin (6) also showed xanthine oxidase inhibitory activity, with IC(50) values of 52.1 and 22.4 muM, respectively. In the test for elastase inhibitory activity, phloretin (5) and 3-hydroxyphloretin (6) were the most potent compounds. Phloretin (5), 3-hydroxyphloretin (6), and quercetin (7) showed better inhibition of MMP-1 production in fibroblast cells. To the best of our knowledge, this is the first time that the active phenolic compounds from M. doumeri var. formosana have been isolated, reported, and described. The above results suggest that the extract of M. doumeri var. formosana containing phenolic compounds could be suitable naturally occurring active constituents for use in anti-aging or cosmetic products.  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