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   1595篇
  免费   87篇
  国内免费   1篇
耳鼻咽喉   61篇
儿科学   57篇
妇产科学   46篇
基础医学   188篇
口腔科学   17篇
临床医学   116篇
内科学   315篇
皮肤病学   24篇
神经病学   123篇
特种医学   33篇
外科学   284篇
综合类   36篇
预防医学   80篇
眼科学   56篇
药学   88篇
中国医学   6篇
肿瘤学   153篇
  2023年   14篇
  2022年   40篇
  2021年   60篇
  2020年   39篇
  2019年   41篇
  2018年   62篇
  2017年   38篇
  2016年   51篇
  2015年   52篇
  2014年   62篇
  2013年   99篇
  2012年   137篇
  2011年   138篇
  2010年   89篇
  2009年   78篇
  2008年   93篇
  2007年   90篇
  2006年   97篇
  2005年   85篇
  2004年   66篇
  2003年   69篇
  2002年   67篇
  2001年   20篇
  2000年   17篇
  1999年   15篇
  1998年   6篇
  1997年   5篇
  1996年   6篇
  1995年   7篇
  1994年   4篇
  1993年   5篇
  1991年   2篇
  1990年   1篇
  1989年   1篇
  1988年   3篇
  1986年   1篇
  1985年   2篇
  1984年   3篇
  1983年   2篇
  1982年   1篇
  1981年   1篇
  1980年   2篇
  1979年   3篇
  1978年   2篇
  1977年   5篇
  1967年   1篇
  1964年   1篇
排序方式: 共有1683条查询结果,搜索用时 15 毫秒
101.
102.
Anal endosonography and its role in assessing the incontinent patient   总被引:3,自引:0,他引:3  
Anal endosonography is now recognized as an important investigation in the assessment of faecal incontinence. The endosonographer needs to be aware that the anatomy of the anal sphincter is complex and therefore there can be pitfalls in the interpretation of images. The findings have clinical implications on subsequent management and can contribute to prognosticating outcome. However, anal endosonography has a complementary role and other investigations, such as anal manometry, should be performed before intervention.  相似文献   
103.
104.
Surgical robotics and laparoscopic training drills   总被引:6,自引:0,他引:6  
PURPOSE: We investigated the impact of robotics on surgical skills by comparing traditional laparoscopy with the da Vinci Surgical System in the performance of various laparoscopic training drills. SUBJECTS AND METHODS: Twenty-one surgeons performed eight timed drills of increasing difficulty with a laparoscopic trainer and the da Vinci Surgical System (Intuitive Surgical Sunnyvale, CA). The mean time to drill completion, drill time variance, and statistical analysis were performed. Surgeons were also questioned about their perception of the robotic technology following completion of the drill series. RESULTS: The mean time required to complete the first drill was 69 seconds with laparoscopy and 57 seconds with the robotic system. The mean times for drill two were 67 seconds with laparoscopy and 44 seconds with robotics; for drill three, the times were 88 seconds for laparoscopy and 61 seconds for robotics, and for drill four, 186 seconds with laparoscopy and 71 seconds with robotics. Only the first drill failed to show a statistically significant difference between the laparoscopic and robotic groups. CONCLUSIONS: The robotic system allowed surgeons to complete drills faster than traditional laparoscopy. Novice laparoscopic surgeons performed three of the four drills faster robotically than did expert laparoscopic surgeons. These findings may indicate that the attributes of the robotic system level the playing field between surgeons of different skill levels. The next generation of surgeons must focus on this evolving technology and its application in the operating room of the future.  相似文献   
105.
BACKGROUND: After performing more than 500 robotic radical prostatectomy and robotic radical cystoprostatectomy in men, we attempted to develop the technique of robot-assisted radical cystectomy in women. This article describes two techniques of robot-assisted radical cystectomy for women, conventional and with preservation of the uterus and vagina. To the best of our knowledge, this is the first case series of robot-assisted radical cystectomy and urinary diversion in women. STUDY DESIGN: Robot-assisted radical cystectomy was undertaken in three female patients with transitional cell carcinoma of the urinary bladder. The operation was performed with the conventional anterior approach in one patient and with a new technique in two patients, which allows preservation of urethra, uterus, vagina, and both ovaries. As planned, the radical cystectomy was done robotically, using the da Vinci Surgical System (Intuitive Surgical). The bladder was entrapped in an Endocatch bag and removed through a small subumbilical incision. Urinary reconstruction was performed extracorporeally after exteriorizing the bowel through the incision used for retrieving the specimen. In two patients, the reconstructed pouch was placed in the pelvis and the abdominal incision was closed. Urethroneovesical anastomosis was done robotically, using a technique described previously for men. RESULTS: The average operating time for the robotic radical cystectomy was 160 minutes and the mean operating times for ileal conduit and orthotopic neobladder were 130 minutes and 180 minutes, respectively. The mean blood loss was less than 100 mL. The mean number of lymph nodes removed was 12 (range 3 to 21). Surgical margins were free of tumor in all three patients. CONCLUSIONS: This approach incorporates advantages of minimally invasive and open surgery. Performing the radical cystectomy with the robot allows precise and rapid removal of the bladder with minimal blood loss. Extracorporeal reconstruction of the urinary tract reduces operative time at this stage of evolution of laparoscopic and robotic instrumentation. In the future, with the development of technology, instrumentation, and with additional refinement of our technique, the entire procedure may be done completely intracorporeally with equal efficiency.  相似文献   
106.
107.
Mother-to-child transmission of hepatitis E virus infection   总被引:4,自引:0,他引:4  
Objectives : Water borne or enterically transmitted non-A-non-B hepatitis is a major public health problem in India. Many of these cases carry fatal outcome. The hepatitis E virus (HEV) has been considered to be the most important causative agent of this entity. The severity and fatality rates of HEV infection are reported to be rather more in pregnant women. However, there is meager information from India, on mother to child transmission of this agent.Methods : During 1997-98, we studied 60 pregnant women suspected to have acute viral hepatitis to understand the frequency of various viral etiologies, disease course and outcome of the pregnancy. Six cord blood samples were tested for IgG, and IgM antibodies against hepatropic viral agents and also for hepatitis E virus RNA by RT-nested PCR using ORF-1 as target.Results : Of the 60 pregnant patients hospitalised at All India Institute of Medical Sciences, New Delhi for acute hepatitis, 22 (37%) were positive for IgM anti-HEV antibodies and 10% were infected with hepatitis B virus. Co-infection of HEV with Hepatitis B and C was seen in 1 and 2 patients, respectively. Most (72%) of the HEV infected patients were in third trimester of pregnancy (P<0.05). Of the 6 cord blood samples tested 3 (50%) were positive for HEV RNA. Though, all mothers were RNA positive, half of the babies did not get infectedin utero with HEV. Fourteen of the 22 (63.6%) HEV infected mothers developed fulminant hepatic failure and all died.Conclusion : The mortality rate in HIV infected mothers was 100%. Mother to child transmission of hepatitis E virus infection was established in 50%  相似文献   
108.
Dey RK  Ray AR 《Biomaterials》2003,24(18):2985-2993
This work reports the development of new non-thrombogenic polymers based on the linear polymers of polyamidoamines (PAAs), having heparin binding ability, obtained by polyaddition of secondary amines to N,N'-methylene bis-acrylamide. PAAs could not be used directly in the making of blood-contacting materials due to their poor mechanical strength. In order to overcome this lacuna, copolymers of amidoamine with methylmethacrylate (MMA) were prepared. Characterization studies indicated that the PAAs have been suitably incorporated into the MMA matrix. The relative hydrophilic nature of the synthesized copolymers was established from the measurement of water contact angle. The heparinized copolymers showed significant improvement in non-thrombogenic characteristics.  相似文献   
109.
110.
We have previously shown that short-term exposure to ethanol stimulates immunoreactive beta-endorphin (IR-beta-EP) release from hypothalamic neurons and that chronic ethanol exposure decreases the IR-beta-EP release from these neurons. The role of protein kinase C (PKC) in the ethanol-regulated beta-EP release from hypothalamic neurons has not been established. In this study, by using the primary cultures of hypothalamic neurons, we tested the effects of PKC stimulator phorbol ester 4 beta-phorbol 12-myristate-13-acetate (PMA) and PKC inhibitor chelerythrine chloride on ethanol-induced IR-beta-EP release. Additionally, the effects of ethanol with or without PMA on expression and translocation of various PKC isoenzymes from cytosolic to membrane fraction were determined. PMA treatment increased IR-beta-EP release in a time- and dose-dependent manner. Acute ethanol treatment (3 h) increased, while chronic ethanol treatment (24 h) reduced, the magnitude of PMA-induced IR-beta-EP release. The stimulatory effect of acute ethanol on IR-beta-EP release was reduced by chelerythrine chloride. Determination of the effects of ethanol with or without PMA on seven different PKC isoenzymes (PKC-alpha, -beta I, -beta II, -gamma, -delta, -epsilon, and -zeta) revealed that the expression and translocation of only two PKC isoenzymes, PKC-delta and PKC-epsilon, were stimulated by acute treatment with ethanol. Acute ethanol also increased PMA-stimulated expression of these two isoenzymes. Chronic ethanol treatment reduced both basal and PMA-induced increase of PKC-delta and PKC-epsilon expression and translocation. These data provide evidence for the first time that ethanol-regulated IR-beta-EP secretion is controlled by the PKC system, possibly involving PKC-delta and PKC-epsilon isoenzymes.  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