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   23302篇
  免费   2103篇
  国内免费   1253篇
耳鼻咽喉   9篇
儿科学   175篇
妇产科学   18篇
基础医学   1704篇
口腔科学   42篇
临床医学   1959篇
内科学   4657篇
皮肤病学   30篇
神经病学   517篇
特种医学   483篇
外国民族医学   41篇
外科学   2985篇
综合类   4799篇
现状与发展   1篇
预防医学   824篇
眼科学   13篇
药学   1973篇
  27篇
中国医学   1356篇
肿瘤学   5045篇
  2024年   72篇
  2023年   373篇
  2022年   746篇
  2021年   948篇
  2020年   847篇
  2019年   689篇
  2018年   609篇
  2017年   784篇
  2016年   935篇
  2015年   939篇
  2014年   1394篇
  2013年   1625篇
  2012年   1312篇
  2011年   1410篇
  2010年   1080篇
  2009年   999篇
  2008年   1090篇
  2007年   1287篇
  2006年   1016篇
  2005年   994篇
  2004年   806篇
  2003年   669篇
  2002年   645篇
  2001年   654篇
  2000年   621篇
  1999年   482篇
  1998年   449篇
  1997年   373篇
  1996年   356篇
  1995年   373篇
  1994年   333篇
  1993年   256篇
  1992年   213篇
  1991年   210篇
  1990年   183篇
  1989年   162篇
  1988年   149篇
  1987年   102篇
  1986年   59篇
  1985年   60篇
  1984年   71篇
  1983年   44篇
  1982年   44篇
  1981年   36篇
  1980年   37篇
  1979年   30篇
  1978年   18篇
  1977年   20篇
  1976年   17篇
  1975年   12篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Background: Gastro-gastric fistulas and marginal ulcers are frequent and serious complications of gastric compartmentalization procedures for obesity. Methods: The authors analyzed 810 patients after 911 operations for gastro-gastric fistulas and marginal ulcers over an 8-year period. All patients underwent a form of gastric bypass, in which a pouch is constructed along the lesser curvature of the stomach. The outlet of the pouch was restricted with a prosthetic band. In the first 189 patients (Group I), the pouch and stomach were stapled in continuity or partially divided. In the next 222 patients (Group II), segments were stapled and separated by transection. In the remaining 492 cases (Group III), in addition to transection of the stomach, a limb of jejunum was interposed between the pouch and excluded stomach. Stapled anastomoses were done in Group I and II patients and a portion of Group III patients. The remaining patients underwent hand-sewn anastomosis. Results: Gastro-gastric fistulas occurred in 49% of the patients in Group I, 2.6% of those in Group II, and 0% of those in Group III. In stapled anastomosis, the incidence of marginal ulceration in Groups I, II, and III were 8.5%, 5.4%, and 5.1%, respectively. In a subset of Group III patients, in whom a two-layer, hand-sewn anastomosis was done, the incidence was 1.6% when the outer layer was not absorbable and 0% when both layers were absorbable. Conclusions: Gastro-gastric fistulas and marginal ulcerations are likely the result of breakdown of the mucosa resulting from migrating staples and other foreign material. Lack of integrity of the gastric lining facilitates the action of the gastric digestive process. Transection of gastric segments with interposition of jejunum prevents gastro-gastric fistula formation. An intact serosa appears to block the digestion of bowel wall by gastric enzymes. Our early data suggest that the use of absorbable sutures at the gastrojejunostomy significantly decreases the incidence of marginal ulceration.  相似文献   
52.
Success Habits of Long-Term Gastric Bypass Patients   总被引:1,自引:1,他引:0  
Background: By identifying common habits of the most successful long-term gastric bypass patients, one is able to establish more specific guidelines for new patients to follow. The first postoperative year is a critical time that must be dedicated to changing old behavior and forming new, lifelong habits. Methods: 100 gastric bypass patients from 1979 to 1995 participated in a comprehensive survey. Surveys were completed in person, by phone, or in writing. Participants were asked to answer questions regarding their eating, drinking, sleeping, exercise, and personal habits. Results: The survey revealed that specific habits are common in gastric bypass patients who have maintained their weight loss for many years. Conclusion: Identifying and defining the common habits of patients who are successful with long-term weight loss enabled specific guidelines to be established for new patients to implement during the initial weight loss phase, which will contribute to life-long success.  相似文献   
53.
Background: The Swedish adjustable gastric band (SAGB) has been in use since 1985. The aim of this study was to analyze short and long-term complications linked to the SAGB. Materials and Methods: Between August 1990 and December 1996, we operated on a series of 326 patients (78 men and 248 women) at the Huddinge University Hospital and the Norra ?lvsborg County Hospital. The mean age of patients at surgery was 40 years (range 19-62). The mean preoperative weight was 125 kg (range 81-181). The mean excess weight was 80%. Results: The mean time of follow-up was 28 months (range 6-76). Complications requiring reoperation included two (0.6%) band dislocations, six (1.8%) band leakages, and 16 (4.6%) band migrations-erosions. The most common reason for abdominal reoperation, band migration, was attributed to overfilling of the band system. In the patients in whom migration occurred, the bands had been filled with a mean volume of 12.6 ml fluid. In the remaining patients, the mean volume was 8.7 ml. The most common complication not requiring reoperation was reflux disease (4.7%). In cases with a small pouch, this complication did not seem to be a serious problem. The mean excess weight loss in the 296 patients without complications was 68%. Conclusion: The overall long-term complication rate following SAGB is reasonable. With improved operating technique and closer follow-up, it should be possible to reduce the complication rate further. Reoperation because of band migration appears to be related to overfilling of the system and should therefore be avoidable in most cases.  相似文献   
54.
Background: The definition of success and failure of a bariatric procedure should include weight loss as well as improvement of comorbidity and quality-of-life (QoL) assessment. QoL measures changes in physical, functional, mental, and social health in order to evaluate benefits of new programs and interventions. Material and Methods: From April 1995 until March 1999, 287 patients underwent laparoscopic adjustable silicone gastric banding (LASGB) at Northwest Hospital Frankfurt a.M. (Germany). In this study, 100 of 287 patients (preoperative mean BMI 48.3 kg/m2; mean age 35.2 years) with a follow-up >18 month were evaluated. All patients underwent anonymous questionnaire (26 questions with a maximum score of 60) about different aspects of QoL outcome after LSAGB. Results: In this study, 4 of 100 patients refused to give an answer to the QoL questions. Therefore 96 patients were evaluated. The QoL auto-evaluation of the patients shows that QoL generally improved after surgery in 92%. Using the scoring system, 44% of patients have excellent, 52% good, and only 4% bad results. The 4 patients who refused had to be classified as failure. General acceptance of LSAGB is wide, but gastrointestinal side effects are recognizable in more than 78% of operated patients. Successful weight loss is followed by an improvement of comorbidities. Conclusions: Safe, effective bariatric procedures increase the quality of life in morbidly obese patients markedly. Bariatric surgeons are committed to support and help their patients until they reach a new quality of life after obesity surgery.  相似文献   
55.
豚鼠应激性胃溃疡模型的制作与验证的实验研究   总被引:5,自引:0,他引:5  
该实验首次应用豚鼠水浸拘束法制作应激性胃溃疡的模型,从胃溃疡指数、应激前后胃电活动的变化、胃粘膜病理改变等方面观察应激性胃溃疡的发生、发展过程。该实验模型易制作,重复性好,适合应用于应激性胃溃疡的实验研究。  相似文献   
56.
The contents of 10 minor and trace elements in histologically confirmed gastric adenocarcinomas and their corresponding normal gastric mucosal tissues obtained from 39 patients at the time of gastric resection were simultaneously determined by instrumental neutron activation analysis. Specimens were irradiated by reactor neutrons and subsequently subject to direct analysis using a high-resolution HPGe -spectrometer. Univariate analysis revealed that gastric cancer tissues had significantly higher concentrations of Fe, K, Mg, Na, Rb, Se, and Zn than normal gastric mucosal tissues. However, multivariate analysis found that Fe, K, and Se were independent elements that associated with gastric cancer. Upon further evaluation of their clinical significance, we found a high tissue K level was related to lymphatic duct metastasis. High Se tissue levels were linked to intestinal type adenocarcinoma. A positive correlation was found between high Fe levels and vascular involvement. These findings suggest that Fe and K are associated with gastric cancer progression. Se is involved in carcinogenesis of stomach in high-risk areas. The mechanisms that underlie the corresponding pathohistological features deserve further study.  相似文献   
57.
Acid inhibition increases gastric mucosal susceptibility to damage by luminal acid. This might be due to reduced metabolic CO2 and bicarbonate whereas, during normal acid, secretion cytoprotective CO2/HCO3- production parallels acid production. Metabolic activity and mucosal damage caused by luminal acid perfusion was determined in anin vitro mouse stomach, with and without acid inhibition, and at 0%, 1%, or 5% serosal CO2 supply. Without acid inhibition there was no mucosal damage at any level of serosal CO2/HCO3- supply. Acid inhibition reduced metabolic CO2 production by 29% (P<0.004) and resulted in microscopic damage to 55% of the mucosal area and perforation in four of five stomachs (P<0.05). Although, 1% CO2 supply completely replaced the reduction in metabolic CO2, it did not protect against mucosal damage. Overreplacement by 5% serosal CO2/HCO3- was required to prevent damage. There was no correlation between luminal CO2/HCO3- output and mucosal damage. The protection by endogenous or exogenous CO2/HCO3- appears to act intracellularly rather than by intragastric or intercellular neutralization.This study was supported by Swiss National Foundation grants 32-26369.89 and 32-33626.92. The morphometry equipment was supported by a grant from the Osterreichische Nationalbank.  相似文献   
58.
Background: Pouch volume appears to be of major importance for subsequent weight loss following any gastric restriction type of surgery for morbid obesity. In order to be able to evaluate pouch volume following Swedish Adjustable Gastric Banding (SAGB), an endoscopic pouch volume classification system was designed in which pouch volume is classified in five categories. The aim of this study was to validate the endoscopic classification system using MRI and barium swallow as reference methods for pouch volume measurement. Methods: Twenty patients (13 women and seven men) were operated for obesity with SAGB. They were investigated a mean of 3 years (6 weeks-5.5 years) after surgery and had at that time lost a mean of 60 (12-112) kg. During the same afternoon they sequentially underwent endoscopy, MRI and barium swallow with an empty stomach. Results: The mean pouch volume measured with MRI was 70 ml (0-180 ml) and with barium swallow was 72 ml (0-195 ml). In 17/20 patients the volume as measured by MRI and barium swallow was in the same volume category as with endoscopy. The correlation measured according to Pearson was significant between endoscopy on one hand and MRI/barium swallow both independently and together (p < 0.001). Conclusion: Based on these results we are confident in using our endoscopic classification system for postoperative follow-up of pouch volume.  相似文献   
59.
Background: The cottage cheese test was developed in an attempt to find a simple way to measure functional pouch volume and to better understand the fate of the tiny proximal pouch following the gastric bypass procedure. Methods: Our patients were asked to eat cottage cheese in a structured fashion before their return visits from 3 months to 2 years postoperatively. Results: We found there was a step-wise progression of increase in functional pouch volume with statistical significance between each time interval. Also, we compared the patients' excess weight loss at 1, 2, and 3 years postoperatively to their pouch size at 1 year postoperatively. Although there is a wide range (2.5-9.0 oz) of pouch sizes at 1 year, there is no significant difference in excess weight loss between the smaller and larger pouches. Conclusions: The pouches enlarge by the orderly process of hyperplasia. Within the 2.5-9 oz volume variation, the pouch volume alone is not a predictor of weight loss. Rather, how the patient uses the pouch/tool, in addition to the other behavior modifications, determines the degree of weight loss. This data strongly suggests that the surgeon's understanding of and teaching of the optimal use of the pouch/tool may be more important than previously thought.  相似文献   
60.
Background: The pharmacokinetic variables of drug clearance and volume of distribution are usually corrected for body weight or surface area. Only recently have the relationships which exist between body size, physiologic function and pharmacokinetic variables been evaluated in the obese population. These effects are not widely known, and data on this and the effects of bariatric surgical procedures are scantily documented in the surgical literature. Methods: Literature review. Results: Drugs with a low or moderate affinity for adipose tissue have a moderate increase in the volume of distribution (Vd), and this correlates with the increase in lean body mass (LBM). Highly lipophilic drugs, with some exceptions, show the expected increase in Vd and prolongation of elimination half-life, indicating a marked distribution into adipose tissue. Drug absorption, in general, is slowed by delayed gastric emptying and is normal when gastric emptying is normal or increased. Most drug absorption occurs in the small intestine where duration of drug/mucosal contact is the most important factor. Conclusions: Drugs whose distribution is restricted to LBM should utilize a loading dose based on ideal body weight (IBW). For those drugs which distribute freely into adipose tissue, the loading dose should be based on total body weight (TBW). Adjustment of the maintenance dose depends on clearance rates. In a few cases dosage adjustment depends on pharmacodynamic data, since drug clearance does not conform to these recommendations, for reasons which remain to be defined. Following bariatric surgery, in the absence of delayed gastric emptying or uncontrolled diarrhea, drug absorption rates are usually comparable to the non-operated patient.  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