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   11178篇
  免费   1262篇
  国内免费   34篇
耳鼻咽喉   62篇
儿科学   289篇
妇产科学   375篇
基础医学   1537篇
口腔科学   200篇
临床医学   1273篇
内科学   2602篇
皮肤病学   184篇
神经病学   1303篇
特种医学   470篇
外科学   1208篇
综合类   216篇
一般理论   11篇
预防医学   1147篇
眼科学   157篇
药学   687篇
肿瘤学   753篇
  2021年   120篇
  2020年   111篇
  2019年   147篇
  2018年   172篇
  2017年   153篇
  2016年   165篇
  2015年   208篇
  2014年   272篇
  2013年   375篇
  2012年   525篇
  2011年   510篇
  2010年   305篇
  2009年   292篇
  2008年   556篇
  2007年   525篇
  2006年   478篇
  2005年   486篇
  2004年   402篇
  2003年   361篇
  2002年   314篇
  2001年   314篇
  2000年   368篇
  1999年   313篇
  1998年   155篇
  1997年   137篇
  1996年   162篇
  1995年   110篇
  1994年   105篇
  1993年   98篇
  1992年   254篇
  1991年   275篇
  1990年   252篇
  1989年   235篇
  1988年   210篇
  1987年   227篇
  1986年   245篇
  1985年   232篇
  1984年   167篇
  1983年   152篇
  1982年   109篇
  1981年   93篇
  1980年   95篇
  1979年   170篇
  1978年   105篇
  1977年   93篇
  1975年   97篇
  1974年   101篇
  1973年   102篇
  1972年   93篇
  1971年   92篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
The Gastric Bypass for Failed Bariatric Surgical Procedures   总被引:1,自引:0,他引:1  
Fox SR  Fox KS  Oh KH 《Obesity surgery》1996,6(2):145-150
Background: Revision of failed bariatric surgical procedures is a significant challenge for every bariatric surgeon. Methods: Evaluated are surgical difficulties, management problems and weight loss in patients with distal gastric bypass as a revisionary procedure. Eighty patients were followed up to 3 years; four were lost to follow-up. Mean age was 43; mean prebariatric surgery weight 134 kg; height 1.65 meters; body mass index 40.1; ideal body weight 62.7 kg; excess weight 70.5 kg; per cent excess weight 214%. A 250 cm stomach-to-ileocecal valve segment of small bowel was used, and the biopancreatic secretions were brought into the terminal ileum 100 cm from the ileocecal valve. Mean pouch size was 63 cc; length of hospital stay 5 days; operative blood loss 616 cc; operative time 130 min. Results: Intraoperative complications included three splenic injuries (without splenectomy). Early complications included one deep vein thrombosis, two marginal ulcers, one GI hemorrhage, one wound dehiscence, one pouch outlet obstruction and one pancreatitis. Late complications included: one death from protein malnutrition/ARDS; 21 hypoproteinemia; six protein malnutrition, and of these, three had hyperalimentation; three cholecystitis; 27 anemia; 22 incisional hernia; two staple-line disruption (reoperated); 26 low serum iron; 11 prolonged (> 6 months) diarrhea; three prolonged frequent vomiting; and two unrelated deaths (chronic myelogenous leukemia and amyotrophic lateral sclerosis). Mean excess weight loss was 83% at 12 months; 89% at 24 months; and 94% at 36 months. Conclusion: The distal gastric bypass is fraught with the operative and immediate post-operative complications experienced in any revisionary bariatric surgery. Distal gastric bypass is very effective in producing long-term weight loss. Nutritional problems are common but usually easily corrected. The most serious nutritional complication is protein malnutrition, which must be identified and corrected early. Success of this procedure is dependent upon patient compliance with proper nutrition and supplements, and regular office follow-up with monitoring of laboratory data. Patients who are noncompliant are at significant risk for complications.  相似文献   
102.
103.
DRGs can be the basis of an effective system of management control because they facilitate comparisons of indicators within and among hospitals.  相似文献   
104.
105.
Summary The effects of three different opioid agonists on contractions and [3H]-acetylcholine (ACh) release evoked by 5-hydroxytryptamine3 (5-HT3) and neurokinin-3 (NK-3) receptor activation were examined in the guinea-pig ileum longitudinal muscle-myenteric plexus strip (LMMP) preparation. The selective mu ()-opioid receptor agonist (d-Ala2,NMe-Phe4,Gly-ol]-enkephalin) (DAMGO; 1 nM–100 nM) and the selective kappa ()-opioid receptor agonist U50488 (10 nM -1 M) inhibited contractile responses to 5-HT and to the selective NK-3 receptor agonist senktide, producing a concentration-related progressive flattening of their concentration-response curves. IC50 estimates for DAMGO and U50488 were somewhat higher for inhibition of 5-HT-evoked as compared to senktide-evoked contractions, and overall lay in the range 6 nM – 51 nM. The selective delta ()-opioid receptor agonist [d-Pen2,5]-enkephalin (DPDPE) inhibited contractile responses only at the highest concentration used (1 M). 3H-overflow from LMMP preparations preincubated with [3H]-choline was measured as an indicator of [3H]-ACh release. DAMGO (1 nM –100 nM) and U50488 (10 nM -1 M) inhibited the increases in release of [3H]-ACh evoked by 5-HT (10 M) and by senktide (10 nM) in a concentration-dependant manner. IC50 estimates for DAMGO and U50488 were not significantly different for inhibition of 5-HT as compared to senktide-evoked increases in [3H]-ACh release and lay in the range 6 nM –23 nM. DPDPE again only inhibited these responses at the maximum concentration used (1 M). The inhibitory effects of DAMGO, U50488 and DPDPE on contractions and [3H]-ACh release evoked by 5-HT and senktide were completely reversed by naloxone (10 M).These results show that ACh release in the guinea-pig ileum evoked by 5-HT and senktide can be modulated to a similar extent by the opioid agonists DAMGO and U50488, but not by DPDPE. This suggests that the pathways of excitation for 5-HT3 and NK-3 receptors converge at some level susceptible to opioid inhibition, which may be mediated by - and -, but not -, opioid receptors.  相似文献   
106.
A Fox  K Fox 《Infection and immunity》1991,59(3):1202-1205
Although it is clear that muramyl peptides are involved in sleep associated with bacterial infection, their role in normal physiological sleep is less certain. It has been speculated that "natural" muramyl peptides, derived from degraded gut flora, may pass into the bloodstream, where they play a role in normal sleep (M. Karnovsky, Fed. Proc. 45:2556-2560, 1986). Muramic acid serves as a chemical marker for muramyl peptides, since it is not synthesized by mammals. After injection of synthetic muramyl dipeptide in rabbits, muramic acid was readily detected (after release by acid hydrolysis) in the circulation; however, levels rapidly decreased. This was an important positive control in assessing circulating levels of natural muramyl peptides. Muramic acid was not found in normal serum (detection limit, approximately 500 pmol/ml), demonstrating the absence of appreciable amounts of circulating natural muramyl peptides. At this time we are unable to provide supportive evidence for Karnovsky's hypothesis.  相似文献   
107.
Fox SR 《Obesity surgery》1991,1(1):89-93
The dilemma with which every bariatric surgeon is confronted is: What to do with the inevitable failures? In vertical gastric partitioning, revising the gastroplasty results in a high second failure rate. In an effort to improve the Success rate in failed gastroplasty patients who request revisionary surgery, the biliopancreatic bypass (classic Scopinaro procedure) was carried out on 57 patients. They have been followed for up to 10 years. The long-term weight loss has averaged 69.4 lb, which is 87% of the pregastroplasty excess weight. The price paid by these patients, in terms of complications, has been significant. Twenty-two Percent have developed hypoalbuminemia with its accompanying peripheral edema; 24% have required i.v. hyperalimintation because Of malnutrition. Sixteen percent of the patients developed a late post-op bowel obstruction, one resulting in death. Osteomalacia, spontaneous fractures have occurred. The biliopancreatic diversion procedure (BPD) is an effective weight-loss operation in the failed gastroplasty patients, but a significant price must be paid in terms of careful follow-up, nutritional deficiencies, and rehospitalizations.  相似文献   
108.
Selection and mortality differentials.   总被引:8,自引:5,他引:3       下载免费PDF全文
The Office of Population Censuses and Surveys Longitudinal Study provides reliable mortality data by a much wider range of characteristics than are available for other national sources. Although it is based on only a 1% sample of the population, it broadens the scope of mortality analysis and permits study of changes in relationships using different aspects of the time dimension. Data from this study have made us increasingly aware of the importance of selection to the interpretation and understanding of observed mortality differentials. Here we focus on that aspect of selection called "health-related mobility," which is associated with the relative health of people acquiring or losing individual characteristics. It is suggested that, for characteristics affected by health-related mobility, mortality differentials would narrow or widen with increased duration of follow-up. One of the basis of this argument the contribution of health-related mobility to mortality differentials by economic position and social class, to regional differentials, and to family and household differentials is investigated. Selection can thus be shown to operate when people change economic position, when they migrate, or when they change marital status. While the effects of these selection processes can be shown to contribute to social class gradients they do not explain regional differentials and contribute only to a limited degree to differentials by marital status. Differentials by household circumstances also reflect the product of selection processes.  相似文献   
109.
110.
The etiology and surgery of senile entropion are reviewed. Many of the presumptive causes of this clinical entity including the vague neurological etiology which caused it to be labeled "spastic" have been found baseless, and the explanation of the elder Fuchs, later confirmed by Duke-Elder, that the cause of senile entropion is due to degenerative tissue changes has been found to be more logical and more compatible with the anatomic findings. There have always been two methods of surgical repair of senile entropion: (1) unwinding the lid by resection of horizontal strips of skin or skin and muscle, and (2) by resection of vertical spindles and triangles of tissue to tauten the lids horizontally. I prefer the latter technique.  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