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   328篇
  免费   28篇
  国内免费   8篇
儿科学   31篇
妇产科学   3篇
基础医学   59篇
口腔科学   10篇
临床医学   33篇
内科学   65篇
皮肤病学   7篇
神经病学   10篇
特种医学   60篇
外科学   22篇
综合类   9篇
预防医学   5篇
眼科学   3篇
药学   28篇
肿瘤学   19篇
  2021年   2篇
  2020年   2篇
  2019年   6篇
  2018年   6篇
  2017年   5篇
  2016年   3篇
  2015年   8篇
  2014年   5篇
  2013年   12篇
  2012年   11篇
  2011年   10篇
  2010年   15篇
  2009年   23篇
  2008年   8篇
  2007年   4篇
  2006年   10篇
  2005年   9篇
  2004年   4篇
  2003年   9篇
  2002年   3篇
  2001年   6篇
  2000年   7篇
  1999年   6篇
  1998年   21篇
  1997年   18篇
  1996年   21篇
  1995年   16篇
  1994年   9篇
  1993年   8篇
  1992年   2篇
  1991年   2篇
  1990年   4篇
  1989年   6篇
  1988年   12篇
  1987年   8篇
  1986年   7篇
  1985年   4篇
  1984年   6篇
  1982年   6篇
  1981年   7篇
  1980年   4篇
  1979年   5篇
  1977年   6篇
  1976年   6篇
  1975年   2篇
  1973年   2篇
  1948年   2篇
  1932年   1篇
  1925年   1篇
  1924年   1篇
排序方式: 共有364条查询结果,搜索用时 15 毫秒
1.
2.
The authors describe their experience with methyl tertiary butyl ether (MTBE) in a larger series of patients than previously reported in order to acquaint physicians with both its effectiveness for dissolution of common bile duct calculi and the limitations of its use. Ten patients with 13 biliary calculi underwent percutaneous stone dissolution treatment with the experimental cholesterol solvent, MTBE. Three stones completely dissolved within 30 minutes, seven were reduced in size, and three were visibly unaffected. All stones not completely dissolved were easily extracted by means of a stone basket except for one in a patient taken to surgery. Although MTBE perfusion is an effective technique for management of biliary calculi, practitioners should be aware that its use is quite time consuming and its odor difficult to control.  相似文献   
3.
The density of Mg(2+)-dependent Ca2+ ATPase in the terminal cisternae of pig skeletal muscle fibers was investigated to discover whether a reduction in Ca2+ ATPase content impairs Ca2+ sequestration and contributes to the elevated myoplasmic Ca2+ concentration in malignant hyperthermia. Unexpectedly, immunogold electron microscopy showed an increase in Ca2+ ATPase, while densitometry of SDS-polyacrylamide gels suggested that the Ca2+ ATPase content of terminal cisternae vesicles did not change. The affinity of Ca2+ ATPase in vesicles for our monoclonal antibody was not altered. We suggest that the availability of antigenic sites in malignant hyperthermia increases after processing for electron microscopy, perhaps as a consequence of altered sarcoplasmic reticulum membrane properties.  相似文献   
4.
Expression of cadherins and CD44 isoforms in ovarian endometrial cysts   总被引:3,自引:0,他引:3  
We evaluated the immunohistochemical expression of cadherins and CD44 variants in 20 endometriomas, 20 cystadenomas, 20 borderline ovarian tumours as well as 20 ovarian carcinomas, and the serological and cystic fluid concentrations of soluble E-cadherin and soluble CD44 standard (sCD44sdt) in 20 endometriomas, 20 cystadenomas, six borderline and 11 carcinomas of the ovary. In endometriomas, immunostaining of E- and N-cadherin was negative (20 and 30% respectively). CD44 H, v3 and v6 immunostaining were detected in 63, 10 and 40% respectively. A difference in immunostaining for E-cadherin was found between endometriomas and cystadenomas (P < 0.001) and for N- cadherin between endometriomas and carcinomas (P < 0.001). A difference in CD44H immunostaining was observed between endometriomas and cystadenomas (P < 0.035) but not with borderline ovarian tumours and carcinomas. No difference in serum concentrations of soluble E- cadherins and CD44 standard was found between the four groups of tumours. Cystic fluid concentrations of E-cadherin were lower in endometriomas than in borderline tumours and ovarian carcinomas (P < 0.001). High concentrations of soluble CD44 standard cystic fluid were found in endometriomas than in other ovarian cysts. Endometriomas and borderline tumours share alterations of cadherins and CD44 isoforms which may help in the understanding of the aggressive and invasive potentials of endometriotic cells.   相似文献   
5.
Genital asymmetry in men   总被引:1,自引:0,他引:1  
This study examined genital asymmetry in a large sample of men. The probands were 6544 non-delinquent men who were interviewed by the Kinsey Institute for Research in Sex, Gender and Reproduction from 1938 to 1963. The measures were four indicators of penile and scrotal asymmetry, along with self-reported handedness, from Kinsey's interview protocol. Most men reported some degree of lateral asymmetry in their flaccid penis and in their testicles; less asymmetry was reported for their erect penis. The asymmetry typically occurred in the left direction, and this pattern occurred in both right- and nonright- handers. However, this 'leftward' pattern was significantly less pronounced in nonright-handers. The results are discussed in relation to previous findings of genital asymmetry in men, the possible relationship of genital asymmetry to functional cerebral asymmetry, and recent data suggesting genital asymmetry may predict patterns of cognitive performance and genital/sexual organ cancers.   相似文献   
6.
Myotonic dystrophy type 1 (DM1) is a debilitating multisystemic disorder caused by a CTG repeat expansion in the DMPK gene. Aberrant splicing of several genes has been reported to contribute to some symptoms of DM1, but the cause of muscle weakness in DM1 and elevated Ca2+ concentrations in cultured DM muscle cells is unknown. Here, we investigated the alternative splicing of mRNAs of two major proteins of the sarcoplasmic reticulum, the ryanodine receptor 1 (RyR1) and sarcoplasmic/endoplasmic reticulum Ca2+-ATPase (SERCA) 1 or 2. The fetal variants, ASI(-) of RyR1 which lacks residue 3481-3485, and SERCA1b which differs at the C-terminal were significantly increased in skeletal muscles from DM1 patients and the transgenic mouse model of DM1 (HSA(LR)). In addition, a novel variant of SERCA2 was significantly decreased in DM1 patients. The total amount of mRNA for RyR1, SERCA1 and SERCA2 in DM1 and the expression levels of their proteins in HSA(LR) mice were not significantly different. However, heterologous expression of ASI(-) in cultured cells showed decreased affinity for [3H]ryanodine but similar Ca2+ dependency, and decreased channel activity in single-channel recording when compared with wild-type (WT) RyR1. In support of this, RyR1-knockout myotubes expressing ASI(-) exhibited a decreased incidence of Ca2+ oscillations during caffeine exposure compared with that observed for myotubes expressing WT-RyR1. We suggest that aberrant splicing of RyR1 and SERCA1 mRNAs might contribute to impaired Ca2+ homeostasis in DM1 muscle.  相似文献   
7.
Immune deficiencies in chronic intestinal pseudo-obstruction   总被引:1,自引:0,他引:1  
Aim: Chronic intestinal pseudo-obstruction has been associated with urinary disorders, myopathy, and ophthalmoplegia in adults and cholelithiasis in children. We observed a high percentage of total-parenteral-nutrition-dependent patients with pseudo-obstruction and recurrent infections requiring gammaglobulin infusions. Methods: AH records for 23 children with chronic intestinal pseudo-obstruction (10 females and 13 males, mean age 9.8 y ± 4.9 y, range 4–24 y) referred for a nutritional evaluation from 1992 to 1995 were reviewed. Chronic intestinal pseudo-obstruction was diagnosed by clinical, radiographic findings and antroduodenal manometry. Intestinal full-thickness biopsies were performed in seven children. Results: Hypogammaglobulinemia was diagnosed in 18 patients (78%): 16 patients had various immunoglobulin deficiencies and 2 had selective antibody deficiency. Intravenous gammaglobulin was administered in 14 patients. Other medical conditions affecting the children are summarized as follows: autonomic dysfunction in 10 patients (43%), recurrent hypoglycemia in 9 (39%), asthma in 9 (39%), cholecystitis in 7 (30%), low serum carnitine level in 6 (26%), urinary dysfunction in 6 (26%), pancreatitis in 5 (22%), behavioral problems in 5 (22%), myopathy in 2 (9%), idiopathic thrombocytopenia in 2 (8%), velopharyngeal insufficiency in 1 (4%), oculocutaneous albinism in 1 (4%), Pierre-Robin syndrome in 1 (4%), and protein C deficiency in 1 (4%). Munchausen syndrome was suspected in two patients. Conclusions: Chronic intestinal pseudo-obstruction appears to be associated with immune deficiencies. It is unclear if the immune deficiencies, intestinal pseudo-obstruction, and the other medical conditions have a common underlying etiology. Repeated infections may be due to impaired immune function in children with chronic intestinal pseudo-obstruction. We recommend screening for immune deficiencies in children with chronic intestinal pseudo-obstruction.  相似文献   
8.
Complications from improperly placed biliary stents are not uncommon. Free loose wires from the ends of an uncovered stent can irritate and damage adjacent mucosal surfaces. Effective management can be achieved via percutaneous placement of a second stent to alter the orientation of the original stent.  相似文献   
9.
Formal assessment of cognitive decline with cognitive tests can be difficult, requiring either two measurement points or a comparison of 'hold' with 'don't hold' tests. Informant-based assessment provides an alternative approach because informants can adopt a longitudinal perspective and directly rate cognitive change. A study was carried out to assess the validity of informant ratings collected by means of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE). A community sample of 500 subjects aged 74 or over underwent four cognitive tests on two occasions 3½ years apart. On the second occasion, informants filled out the IQCODE. Subjects rated as having moderate or severe decline were found to have greater change on the cognitive tests. These findings support the validity of informant ratings of cognitive decline.  相似文献   
10.
Houle  JJ; Hoffmann  EM; Esser  AF 《Blood》1988,71(2):287-292
Our previous work revealed that homologous complement (C) was ineffective in lysing antibody-sensitized erythrocytes (EA) even at high concentrations. It was also shown that activation of complement on homologous EA resulted in the binding of C9 and the formation of EA bearing complement proteins C1 through C9 (EAC1-9), yet few hemolytic sites were formed. Instead, as shown here, the formation of homologous EAC1-9 caused the cells to become resistant to lysis even by heterologous complement during a second incubation. In contrast, when homologous EAC1-8 were produced by incubating EA with C9-depleted serum, such intermediates were not protected against lysis by heterologous complement during a second incubation. Furthermore, homologous C9 on EAC1-9 was able to reduce the hemolytic efficiency of heterologous complement without blocking C activation and the formation of new C5b-9 complexes. Protection was not modified when homologous EAC1-9 were produced in one step, by incubation of EA with serum, or sequentially by adding C9 to EAC1-8. The minimum number of 9-sites required to confer a protective effect on EAC1-9 was less than 200 per cell. Thus, in addition to its known effect in heterologous cell killing, homologous C9 is capable of protecting homologous cells against inadvertent complement lysis.  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