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   7639篇
  免费   689篇
  国内免费   174篇
耳鼻咽喉   86篇
儿科学   328篇
妇产科学   259篇
基础医学   269篇
口腔科学   170篇
临床医学   1382篇
内科学   1692篇
皮肤病学   192篇
神经病学   437篇
特种医学   264篇
外科学   2120篇
综合类   47篇
预防医学   359篇
眼科学   442篇
药学   150篇
中国医学   4篇
肿瘤学   301篇
  2023年   113篇
  2021年   97篇
  2020年   125篇
  2019年   80篇
  2018年   156篇
  2017年   203篇
  2016年   225篇
  2015年   178篇
  2014年   295篇
  2013年   383篇
  2012年   240篇
  2011年   260篇
  2010年   308篇
  2009年   407篇
  2008年   275篇
  2007年   288篇
  2006年   292篇
  2005年   287篇
  2004年   205篇
  2003年   175篇
  2002年   168篇
  2001年   176篇
  2000年   119篇
  1999年   181篇
  1998年   180篇
  1997年   208篇
  1996年   303篇
  1995年   257篇
  1994年   197篇
  1993年   117篇
  1992年   133篇
  1991年   140篇
  1990年   70篇
  1989年   132篇
  1988年   102篇
  1987年   79篇
  1986年   102篇
  1985年   87篇
  1984年   87篇
  1983年   74篇
  1982年   66篇
  1981年   62篇
  1980年   81篇
  1979年   39篇
  1978年   59篇
  1977年   42篇
  1976年   44篇
  1975年   45篇
  1964年   49篇
  1963年   47篇
排序方式: 共有8502条查询结果,搜索用时 46 毫秒
91.
92.
93.
Our aim was to examine the feasibility of a totally laparoscopic insertion of a bifurcated aortofemoral bypass graft in a canine model and to compare the surgical results with those in control animals undergoing standard grafting and laparoscopic-assisted bypass procedures. Using a six-port approach, we exposed and cross clamped the aorta, tunneled a bifurcated Dacron graft, and performed an end-to-end aortic anastomosis while maintaining pneumoperitoneum by means of CO2. Proximal anastomoses were performed with 4/0 double-ended continuous Prolene sutures and distal anastomoses were performed through standard groin incisions. Total operating and aortic cross-clamp times were measured as was the total blood loss for each procedure. Clinical outcome was also documented. Eight female laboratory-bred hounds underwent successful totally laparoscopic aortobifemoral bypass grafting, eight underwent open grafting, and eight underwent laparoscopic-assisted bypass. Mean operating time was 193 minutes in the animals undergoing totally laparoscopic insertion vs. 156 minutes in the open group and 180 minutes in the laparoscopic-assisted group. Aortic cross-clamping time was also significantly longer at 87 minutes vs. 43 minutes (p < 0.001)=" in=" the=" totally=" laparoscopic=" group,=" but=" blood=" loss=" was=" less.=" all=" eight=" laparotomy=" and=" laparoscopic-assisted=" dogs=" were=" still=" alive=" with=" no=" complications=" at=" 28=" days,=" whereas=" three=" of=" the=" eight=" in=" the=" totally=" laparoscopic=" group=" showed=" evidence=" of=" temporary=" paraplegia.=" this=" experimental=" study=" demonstrates=" that=" a=" totally=" laparoscopic=" approach=" can=" be=" used=" to=" insert=" a=" bifurcated=" aortofemoral=" bypass=" with=" a=" proximal=" end-to-end=" anastomosis=" but=" currently=" does=" not=" save=" time=" and=" may=" increase=" the=" risk=" of=" neurologic=">Presented at the Twentieth Annual Meeting of the Peripheral Vascular Surgery Society, New Orleans, La., June 10, 1995.  相似文献   
94.
The success of vertical gastroplasty may be jeopardized by gastric leakage or ulceration due to failure of the technique. Reports of band erosion and staple-line leakage have led us to seek technical improvements to reduce technical failures. We describe a modification to the technique of band placement and a manoeuvre to aid the placement of staples when the TA90 staple gun is used.  相似文献   
95.
Many forms of gastric banding have been described and high reoperation rates reported. These can be mainly attributed to excess vomiting associated both with and without stenosis. Reflux oesophagitis and the ‘sump’ effect may be other causes. This paper examines the problems associated with banding leading to revisional surgery and introduces a new technique, ‘fundal supporting suture’, to correct these problems. Preliminary results on 126 bandings without the modification and 22 with the modification are presented.  相似文献   
96.
97.
98.
Increased placental apoptosis in intrauterine growth restriction   总被引:2,自引:0,他引:2  
OBJECTIVES: Our purpose was to investigate a possible role for apoptosis in the pathophysiologic mechanisms of intrauterine growth restriction. STUDY DESIGN: Placental samples were obtained from 43 uncomplicated third-trimester pregnancies and from 26 pregnancies complicated by intrauterine growth restriction. The definition used to identify cases of intrauterine growth restriction depended on three criteria: clinical evidence of suboptimal growth, ultrasonographic evidence of deviation from an appropriate growth percentile, and individualized birth weight ratios <10th percentile. Light microscopy was used to quantify the incidence of apoptosis. Electron microscopy and TUNEL (terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate nick end labeling) staining were used to confirm the occurrence of apoptosis. RESULTS: Quantification of apoptosis (medians and interquartile ranges) resulted in the following values: normal third trimester (n = 43) 0.14% of cells (0.08% to 0.20%) and intrauterine growth restriction third trimester (n  = 26) 0.24% of cells (0.16% to 0.29%). The incidence of apoptosis was significantly higher in placentas from pregnancies with intrauterine growth restriction compared with normal third-trimester placentas (p < 0.01, Mann Whitney U test). CONCLUSIONS: These results suggest that apoptosis may play a role in the pathophysiologic mechanisms of intrauterine growth restriction.(Am J Obstet Gynecol 1997;177:401)  相似文献   
99.
Congenital tuberculosis is a rare disease. The non-specific nature of presenting signs and symptoms (because of the lack of host response) and the fatal outcome in the absence of early therapy all underscore the importance of early diagnosis and treatment in infants. Recognition requires awareness that tuberculosis at this age has manifestations not found in older children. Here a case of congenital tuberculosis is presented, where changes were confined only to the thorax. Tuberculosis in the mother could be diagnosed only retrospectively.  相似文献   
100.
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