首页 | 官方网站   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   5257篇
  免费   273篇
  国内免费   34篇
医药卫生   5564篇
  2024年   3篇
  2023年   39篇
  2022年   242篇
  2021年   362篇
  2020年   83篇
  2019年   120篇
  2018年   147篇
  2017年   110篇
  2016年   128篇
  2015年   163篇
  2014年   209篇
  2013年   284篇
  2012年   407篇
  2011年   421篇
  2010年   207篇
  2009年   144篇
  2008年   347篇
  2007年   378篇
  2006年   331篇
  2005年   311篇
  2004年   331篇
  2003年   305篇
  2002年   217篇
  2001年   21篇
  2000年   21篇
  1999年   23篇
  1998年   25篇
  1997年   14篇
  1996年   9篇
  1995年   14篇
  1994年   13篇
  1993年   8篇
  1992年   12篇
  1991年   8篇
  1990年   9篇
  1989年   8篇
  1988年   7篇
  1987年   4篇
  1986年   17篇
  1985年   7篇
  1983年   3篇
  1982年   5篇
  1981年   9篇
  1980年   5篇
  1978年   4篇
  1977年   4篇
  1976年   3篇
  1975年   6篇
  1966年   2篇
  1964年   2篇
排序方式: 共有5564条查询结果,搜索用时 15 毫秒
1.
2.
Proprioception is a term covering together joint position sense, kinesthesia and integration of these stimuli in the central nervous system which is needed to keep homeosthasis of joints during motion. The aim of this study is to present authors originally created measuring device working according to the principles of Barrett, aiming at evaluation of proprioception of the knee. The construction of this device is based on the Summer chair, model UPR-01B, working in connection with Bosh goniometer DWM-40L measuring angles with a precision of 0,1 degree. The device presented in this study fulfills all criteria required for this kind of apparatus and may be an alternative to other constructs produced commercially and available on the market.  相似文献   
3.
Objective: Electroporation mediated transfer of plasmid DNA into peripheral muscle results in high transfection efficiency. The aim of this study was to investigate the effect of gene transfer of human IL-10 (hIL-10) into the tibialis anterior muscle (MTA) in combination with low dose Cyclosporine A (CsA) on acute rejection of lung allografts in the rat. Methods: Lung allotransplantation was performed from male BN donor to male Fisher F344 rats. Gene transfer was achieved by intramuscular injection into the MTA of the recipient followed by electroporation (4×20 ms impulses at 200 V/cm) 24 h prior to the transplantation. Group A (n=5) received CsA (2.5 mg/kg bw ip) for 5 days post-transplant and group B (n=5) 2.5 μg of PCIK hIL-10 (plasmid expression vector containing human CMV immediate early gene promoter and enhancer) and a low dose CsA (2.5 mg/kg bw i.p.). Graft function was assessed by blood gas at day 5 after exclusion of the native lung. Animals were sacrificed and blood was drawn to measure serum hIL-10 levels (ELISA) and tissue was sampled for histological grading of rejection. Results: Local expression of hIL-10 was confirmed at the mRNA level by in situ hybridization. All group A control animals showed severe signs of rejection. At day 5 all grafts in group B showed good gas exchange mean PaO2 233±123 mmHg, vs 44±8 mmHg in group A. Histological examination revealed moderate to severe rejection in all animals in group A (IIIB, ISHLT) in contrast to low moderate rejection in group B (II–IIIA). hIL-10 serum levels on day 5 were 14±7 pg/ml in group B vs. 0 in group A. Conclusions: Electroporation mediated hIL-10 overexpression in a peripheral muscle of the recipient in combination with low dose CsA reduces acute rejection in this model of rat lung allotransplantation.  相似文献   
4.
The objectives of this study were to determine the relationship between carotid-femoral (cfPWV) and aortic pulse wave velocity (aPWV) and to compare their modulators and association with coronary artery disease (CAD). We studied 107 consecutive patients (68 men) with a mean age of 60.49+/-8.31 years who had stable angina and had been referred for coronary angiography. cfPWV and aPWV were measured simultaneously during cardiac catheterization using the Complior device and aortic pressure waveform recordings, respectively. Based on the presence or absence of significant coronary artery stenosis (CAS) patients were subdivided into a CAS+ or CAS- group. The mean values of cfPWV and aPWV were 10.65+/-2.29 m/s and 8.78+/-2.24 m/s, respectively. They were significantly higher in the CAS+ (n=71) compared with the CAS- (n=36) group and predicted significant CAS independently of cardiovascular risk factors and mean or systolic aortic blood pressure. aPWV and cfPWV were significantly correlated (r=0.70; p<0.001) but the degree of correlation differed significantly (p<0.03) between the CAS+ (r=0.74, p<0.001) and CAS- group (r=0.46, p=0.003). Age and mean aortic blood pressure were independent predictors for aPWV as well as cfPWV. In the receiver operating characteristic (ROC) analysis, aPWV and cfPWV had similar accuracy in identification of significant CAS (AUC [area under the ROC curve]=0.76 and 0.69, respectively; p=0.13). However, neither cfPWV nor aPWV was effective at differentiating the extent of CAD. In conclusion, aPWV and cfPWV are highly correlated parameters with similar determinants and comparable accuracy in predicting significant CAS. The strength of correlation between these two indices differed significantly between subjects with and those without CAS.  相似文献   
5.
OBJECTIVE: The aim of this study was to assess changes in early and late haemodynamic status after the Norwood procedure (NP), caused by the implementation of right ventricle-to-pulmonary artery shunt (RV-PA). METHODS: A consecutive series of 68 children with hypoplastic left heart syndrome underwent NP: Group 1 (n=31) with the application of a modified Blalock-Taussig shunt and Group 2 (n=37) with RV-PA. Haemodynamic data from the early postoperative period (72 h after the operation) and cardiac catheterisation data, as well as blood tests before the hemi-Fontan procedure (HF) were analysed. Univariate (chi(2) test, Mann-Whitney's and Student's t-tests) and multiple regression analysis were carried out. RESULTS: In Group 1, circulatory collapse requiring resuscitation occurred in 15 (48.4%) children, within 72 h after the procedure. The resuscitation was unsuccessful in nine (29%) cases. The operative mortality (30 days) was 35%. In Group 2, two (5%) children died within the early and two (5%) within the late postoperative period. The postoperative course in the remaining children from Group 2 was uneventful. In Group 2 there was a significantly higher mean diastolic pressure after NP (P<0.05). The arterial pulse pressure after NP was significantly lower in Group 2 (P<0.05). Before HF, the application of RV-PA was associated with a lower Qp:Qs ratio (P=0.020), lower aortic pulse pressure (P=0.004) and lower aortic oxygen saturation (P=0.039). CONCLUSIONS: A stable haemodynamic status due to independent coronary perfusion, higher diastolic and lower pulse pressure is the most advantageous effect of RV-PA, resulting in a lower mortality and morbidity after NP. A lower Qp:Qs ratio eliminates the danger of the ventricular volume overload and ensures good conditions for the development of the pulmonary circulation before HF.  相似文献   
6.
The mechanism by which S-adenosylmethionine (SAM) and adenosine (Ado) increase ATP levels in intact human erythrocytes in vitro has been compared. The use of erythrocytes from healthy controls and from subjects totally deficient in adenine phosphoribosyltransferase (APRT), plus inhibitors of adenosine kinase (AK) and adenosine deaminase (ADA) separately and together, has enabled us to demonstrate that this increment in ATP levels occurred via totally different metabolic routes. The results show that: (i) whilst the Ado-induced increment in ATP was AK dependent, that produced by SAM was independent of AK; and (ii) the SAM-induced increment in ATP was totally dependent on APRT and that some of the increment produced by Ado might also be APRT dependent. The above data are consistent with the metabolism of SAM to ATP by a route recently identified by us whereby ATP is formed from deoxyadenosine: namely binding to the enzyme S-adenosylhomocysteine hydrolase with subsequent release of adenine and further conversion to ATP via APRT.  相似文献   
7.
8.
Flexible Sigmoidoscopy Screening in an Industrial Setting   总被引:1,自引:0,他引:1  
Little is known about the yield of colorectal cancer screening programs in an industrial setting. We therefore established a flexible sigmoidoscopy screening program at a chemical manufacturing plant and offered testing to all employees over the age of 40. After a Fleet enema preparation had been administered, a digital rectal examination and sigmoidoscopy were performed on each volunteer worker in the medical office of the plant. The plant had an average census of about 650 workers; 202 were screened during a 2-yr period. The mean (+/- SEM) age of participants was 52 +/- 0.4. Sixty-four employees had polyps (31.7%); data on follow-up colonoscopy were available in 69%. Colonoscopy revealed adenomatous polyps in 23 workers (53.5%), hyperplastic polyps in 10 (23%), and no evidence of neoplasia in 10 (23%). Seven workers did not arrange for follow-up colonoscopy and 12 individuals could not be contacted. No cancers were detected. In the 40- to 50-yr age group, polyps were detected in 19.5% of employees (25% adenomatous). Incidental findings were common, and included prostatic nodules, hemorrhoids, diverticulosis, and proctitis, among others. We conclude that screening sigmoidoscopy can be conveniently and economically performed at the workplace, with a high yield and good worker acceptance. The high yield suggests a possible association between polyp formation and work in a chemical plant. The finding of adenomatous polyps in the younger patients suggests that the threshold for flexible sigmoidoscopy at age 50 needs to be reassessed.  相似文献   
9.
The aim of the study was clinical and X-ray evaluation of two patients treated because of fractures of shaft of femur with coexisting hip joint osteoarthritis with cemented THR. Both patients were treated just after the injury. Reduction of fractures were made to both patients. Stabilization of fracture in one patient was made with metal plate and cables, stabilization with only cables was made to second patient. Exeter THR with standard stem was implanted to first patient, and with long stem to the second one. Both patients have good clinical results - 90 and 92 pts. in Harris Hip Score after 36 and 48 months accordingly. The fracture healed in the first patient. The evidence of fracture healing of the second patient was impossible to examine because of lack of X-ray. Conclusions. 1) The use of THR in the treatment of femoral shaft fractures with coexisting osteoarthritis gives a chance of simultaneous fracture treatment and joint replacement. 2) Fracture stabilization requires the use of metal plates and cables.  相似文献   
10.
The Avantage double mobility press-fit cup was devised by Dr. Bousquet in the 70's to bring reasonable response to a problem of recurrent dislocation after total hip arthroplasty. The cup is attached to the femoral head by a bipolar polyethylene liner. The polyethylene liner moves freely inside a shiny--polished metal cup. The angular range of motion before impingement is increased by the mobility of the liner. The double connection (cup-liner, liner-head) reduces the stress on the metal cup and improve the stability of the prosthesis. The solution has proved to be efficient in reducing dislocation risk and maintains at the same time the appropriate range of motion. Between January 2004 and November 2005, 113 hip arthroplasties in 108 women with use of the double mobility cup were performed. The cemented version of the Avantage cup was inserted in 15 patients (mean age--76.9 years). Uncemented, HA coated implant was used in 98 patients (with mean age of 55 years). The mean follow-up was 20.4 months. No one patient was lost to follow-up. No postoperative dislocation was observed during follow-up. There was no unwanted leg lengthening greater than 1 cm. The Avantage cup may be indicated in any primary total hip arthroplasty especially in those with increased risk of postoperative dislocations. This cup enables a correct balance of the hip without a need of the unwanted lengthening of the leg.  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-23

京公网安备 11010802026262号