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   6195篇
  免费   685篇
  国内免费   6篇
医药卫生   6886篇
  2021年   91篇
  2020年   68篇
  2019年   82篇
  2018年   121篇
  2017年   87篇
  2016年   80篇
  2015年   83篇
  2014年   114篇
  2013年   157篇
  2012年   226篇
  2011年   256篇
  2010年   114篇
  2009年   145篇
  2008年   193篇
  2007年   248篇
  2006年   251篇
  2005年   203篇
  2004年   211篇
  2003年   236篇
  2002年   229篇
  2001年   237篇
  2000年   189篇
  1999年   176篇
  1998年   69篇
  1997年   65篇
  1994年   70篇
  1993年   68篇
  1992年   162篇
  1991年   185篇
  1990年   150篇
  1989年   154篇
  1988年   146篇
  1987年   146篇
  1986年   137篇
  1985年   130篇
  1984年   96篇
  1983年   87篇
  1982年   64篇
  1981年   72篇
  1980年   65篇
  1979年   82篇
  1978年   76篇
  1977年   73篇
  1976年   74篇
  1975年   63篇
  1974年   74篇
  1973年   74篇
  1972年   73篇
  1969年   67篇
  1968年   63篇
排序方式: 共有6886条查询结果,搜索用时 812 毫秒
1.
2.
3.
Transplanting the Highly Sensitized Patient: The Emory Algorithm   总被引:4,自引:0,他引:4  
Renal transplant patients sensitized to HLA antigens comprise nearly one-third of the UNOS wait-list and receive 14% of deceased donor (DD) transplants, a rate half that of unsensitized patients. Between 1999 and 2003, we performed 492 adult renal transplants from DD; 120 patients (approximately 25%) had a panel reactive antibody (PRA) of >30%, with nearly half (n = 58) having a PRA of >80%. Our approach is based upon high-resolution solid-phase HLA antibody analysis to identify class I/II antibodies and a 'virtual crossmatch' to predict compatible donor/recipient combinations. Recipients are excluded from the United Network for Organ Sharing match run if donors possess unacceptable antigens. Thus, when sensitized patients appear on the match run, they have a high probability of a negative final crossmatch. Here, we describe our 5-year experience with this approach. Five-year graft survival ranged from 66% to 70% among unsensitized (n = 272), moderately sensitized (PRA < 30%, n = 100) and highly sensitized (>30% PRA; n = 120) patients, equal to the average national graft survival (65.7%). The application of this approach (the Emory Algorithm) provides a logical and systematic approach to improve the access of sensitized patients to DD organs and promote more equitable allocation to a highly disadvantaged group of patients awaiting renal transplantation.  相似文献   
4.
Detection of non-palpable early splenic enlargement may aid diagnosis of primary polycythaemia (PP) and primary thrombocythaemia (PT). In this study linear spleen sizing by ultrasound has been compared with spleen volume estimation by single photon emission computerized tomography (SPECT) in 26 patients. Spleen length by ultrasound correlated well with SPECT volume estimation.
Ultrasound spleen length was also measured in 60 normal control subjects where the upper limit of the 95% reference range was 11.6 cm. Changes in spleen length with both age and body weight were substantial and overshadowed the imperfect reproducibility of this method. Therefore, interpretation of an individual's measured spleen length should be in relation to that predicted for adults of the same age and weight, particularly at the extremes of the younger, heavier patients and also the older, lighter patients.
Ultrasound spleen lengths of different patient groups (21 PP, 26 PT, 17 idiopathic erythrocytosis, 12 secondary polycythaemia, nine apparent polycythaemia) were compared both using the measured overall reference range and the differences from the values predicted for their age and weight. The comparison showed that almost all patients with PP whose spleens were not palpable had spleen lengths greater than the upper limit for the normal control group, but separation from the other patient groups was incomplete.
Detection of non-palpable splenomegaly by ultrasound length should remain a 'minor' criterion amongst the 'proposed modified diagnostic criteria' of PP.  相似文献   
5.
Lithium is a widely prescribed drug used for the treatment of bipolar affective illness. Previous reports on its effects on sperm motility and male fertility are conflicting. The effect of lithium on human sperm motility was examined in vitro using the modified transmembrane migration method. This technique takes account of the dilution of lithium that occurs during the incubation. Lithium inhibits human sperm motility in vitro in concentrations comparable with those reported to be achieved in semen after oral administration.  相似文献   
6.
Data from the household portion of the 1977-78 USDA Nationwide Food Consumption Survey were used to determine expenditures for convenience and nonconvenience foods and nutrients from those foods. Households with male food preparers accounted for approximately 15% of the survey population, frequently included only one person, and had a larger proportion of young and elderly heads of household than households with a female food preparer. As a group, the foods most frequently reported in households with male food preparers were quite similar to those used by households with female food preparers. Male food preparers spent less of the food dollar on nonconvenience items than did other food preparers, and conversely they spent more on complex and manufactured convenience foods. Total food energy and nutrient levels per nutrition unit of the foods used by households with male food preparers were significantly higher than those in households with female food preparers for all nutrients except thiamin and riboflavin. However, the values were more than 100% of the Recommended Dietary Allowance values except for vitamin B-6 for both sample groups.  相似文献   
7.
8.
Between 23 and 70% of occupants involved in frontal impacts sustain cervical spine injuries, many with neurological involvement. It has been hypothesized that cervical spinal cord compression and injury may explain the variable neurological profile described by frontal impact victims. The goals of the present study, using a biofidelic whole cervical spine model with muscle force replication, were to quantify canal pinch diameter (CPD) narrowing during frontal impact and to evaluate the potential for cord compression. The biofidelic model and a sled apparatus were used to simulate frontal impacts at 4, 6, 8, and 10 g horizontal accelerations of the T1 vertebra. The CPD was measured in the intact specimen in the neutral posture (neutral posture CPD), under static sagittal pure moments of 1.5 Nm (pre-impact CPD), during dynamic frontal impact (dynamic impact CPD), and again under static pure moments following each impact (post-impact CPD). Frontal impact caused significant (P<0.05) dynamic CPD narrowing at C0-dens, C2-C3, and C6-C7. The narrowest dynamic CPD was observed at C0-dens during the 10 g impact and was 25.9% narrower than the corresponding neutral posture CPD. Interpretation of the present results indicate that the neurological symptomatology reported by frontal impact victims is most likely not due to cervical spinal cord compression. Cord compression due to residual spinal instability is also not likely.  相似文献   
9.
Our case represents the eleventh example of intra-abdominal hemorrhage due to the rupture of a splanchnic artery. Most of the cases occur in the right or the left gastric artery. One occurred in the gastroduodenal and one in the left gastroepiploic artery. Only four cases of the superior mesenteric artery have been noted, including the present case. The association with severe hypertension is rather striking as it occurred in seven of the eleven cases. Six cases showed definite marked arteriosclerosis of the rupture vessel. We feel that hypertension, severe gastrointestinal vascular sclerosis, separately or in combination, are decided factors in the precipitation of rupture of the vessel, comparable to cerebral hemorrhage in hypertension. The infrequency of this accident is probably in part due to the infrequent findings of vascular sclerosis in the intestinal arteries. The clinical symptoms are severe abdominal pain associated with varying degrees of shock. All the patients operated on recovered completely.  相似文献   
10.
Successful treatment of an infected vascular graft with gentamicin beads   总被引:1,自引:0,他引:1  
This short report describes the successful healing of an infected axillo-bifemoral graft by the insertion of Gentamicin beads, this technique cannot be recommended for all infected grafts the majority of which will have to be removed and replaced.  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