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   1157篇
  免费   87篇
  国内免费   4篇
耳鼻咽喉   27篇
儿科学   15篇
妇产科学   4篇
基础医学   119篇
口腔科学   27篇
临床医学   111篇
内科学   213篇
皮肤病学   4篇
神经病学   107篇
特种医学   94篇
外科学   230篇
综合类   9篇
预防医学   59篇
眼科学   55篇
药学   107篇
肿瘤学   67篇
  2023年   8篇
  2022年   13篇
  2021年   29篇
  2020年   11篇
  2019年   28篇
  2018年   46篇
  2017年   18篇
  2016年   28篇
  2015年   25篇
  2014年   21篇
  2013年   43篇
  2012年   84篇
  2011年   83篇
  2010年   34篇
  2009年   21篇
  2008年   55篇
  2007年   58篇
  2006年   46篇
  2005年   60篇
  2004年   53篇
  2003年   49篇
  2002年   45篇
  2001年   30篇
  2000年   36篇
  1999年   26篇
  1998年   9篇
  1997年   18篇
  1996年   13篇
  1995年   13篇
  1994年   13篇
  1992年   28篇
  1991年   17篇
  1990年   38篇
  1989年   18篇
  1988年   18篇
  1987年   15篇
  1986年   17篇
  1985年   14篇
  1984年   4篇
  1982年   5篇
  1979年   8篇
  1978年   5篇
  1977年   4篇
  1976年   6篇
  1975年   4篇
  1974年   3篇
  1973年   4篇
  1972年   3篇
  1967年   3篇
  1966年   4篇
排序方式: 共有1248条查询结果,搜索用时 15 毫秒
1.

Background  

Advances in intensive care medicine have increased survival rates of patients with critical neurological conditions. The focus of prognostication for such patients is therefore shifting from predicting chances of survival to meaningful neurological recovery. This study assessed the variability in long-term outcome predictions among physicians and aimed to identify factors that may account for this variability.  相似文献   
2.
3.
The goal of the present study is to develop a technique for laparoscopic aortobifemoral bypass.Piglets weighing between 60 and 78 kg were anesthetized with halothane. The lateral retroperitoneal approach was preferred to the more familiar anterior transperitoneal approach and was successfully completed in 19 piglets. The piglets were placed in the right lateral decubitus position. The first port (2 cm) was inserted halfway between the tip of the 12th rib and the iliac crest. Four other trocars were placed in the retroperitoneum after balloon inflation had allowed creation of a space which permitted visualization of the aorta from the left renal artery down to the aorto-iliac junction. After evacuation of the retropneumoperitoneum, the cavity was maintained using an abdominal lift device and a retractor.Using this approach, we performed four aortobifemoral bypasses (end-to-end aortic anastomosis) after conventional intravenous heparinization (100 IU/kg) in less than 4 h. Blood loss did not exceed 250 ml and the hematocrit remained stable. Postmortem evaluation of the grafts revealed they were positioned as in a conventional bypass, their limbs having followed in the created retroperitoneal tunnels along the path of the native arteries. No mortality occurred before sacrifice of the animals. We believe that this first performed series of totally retroperitoneal laparoscopic aortobifemoral bypasses in the porcine model is useful in preparation for human application due to the anatomical similarities in the periaortic region.  相似文献   
4.
Retroperitoneal sarcomas are rare tumors representing 0.1% to 0.2% of all malignant tumors. They are usually revealed by an abdominal mass (33%), possibly associated with pain (41%). Edema of the lower limbs is reported in 10% of cases. Acute renal failure with anuria by bilateral ureteral compression, associated with invasion of the inferior vena cava has not been previously reported.  相似文献   
5.
Results of the Ross operation in a pediatric population   总被引:1,自引:0,他引:1  
Objective: To analyse the results of the mid-term clinical and echocardiographic follow-up of the pediatric Ross operation. Methods: Echo-Doppler follow-up of 53 consecutive pediatric Ross procedures performed between 1994 and 2003. Median age was 9.7 years at time of operation (2 weeks–17.7 years). Six patients were younger than 3 months. Median age at follow-up was 15.6 years. Aortic valve/left ventricular outflow tract (LVOT) anomalies were congenital in 49 (92%). Seventy percent had previous surgery or balloon valvuloplasty. Root replacement was used in all. Thirteen patients (25%) had LVOT enlargement. Mean cross-clamp time was 113 (69–189) minutes. Results: Early mortality occurred in 3 patients after emergency surgery following balloon failure (n=1) and extended Ross following interrupted arch/VSD repair (n=2). Late mortality was due to LV fibroelastosis in 2 patients and complicated pulmonary artery stenting in another. RVOT reoperations were required because of late homograft obstruction in 2 patients and because of pulmonary artery stenosis in another. Five patients (9.4%) were reoperated for pulmonary autograft dilatation (n=3) and for leaflet fibrosis or perforation (n=2). Autografts were repaired in two patients, while a mechanical valve was inserted in 3 cases. At 9 years the actuarial survival and event free survival were 89 and 74%, respectively. At last follow-up 90% of autograft diameters indexed to body surface area was above the 90th percentile of normal aortic root diameters. LVOT and RVOT gradients were low and autograft insufficiency was trivial to mild in 84% and mild to moderate in 16%. Autograft stenosis was not noticed. Conclusions: The pediatric Ross procedure remains an important tool but autograft dilatation also occurs in the pediatric population. The significance of this finding has yet to be determined.  相似文献   
6.
PURPOSE: The objective of this survey was to examine the services offered by multidisciplinary pain treatment facilities (MPTFs) across Canada and to compare access to care at these MPTFs. METHODS: A MPTF was defined as a clinic that advertised specialized multidisciplinary services for the diagnosis and management of patients with chronic pain, having a minimum of three different health care disciplines (including at least one medical speciality) available and integrated within the facility. The search method included approaching all hospital and rehabilitation centre administrators in Canada, the Insurance Bureau of Canada, the Workplace Safety and Insurance Board or similar body in each province. Designated investigators were responsible for confirming and supplementing MPTFs from the preliminary list for each province. Administrative leads at each eligible MPTF were asked to complete a detailed questionnaire regarding their MPTF infrastructure, clinical, research, teaching and administrative activities. RESULTS: Completed survey forms were received from 102 MPTFs (response rate 85%) with 80% concentrated in major cities, and none in Prince Edward Island and the Territories. The MPTFs offer a wide variety of treatments including non-pharmacological modalities such as interventional, physical and psychological therapy. The median wait time for a first appointment in public MPTFs is six months, which is approximately 12 times longer than non-public MPTFs. Eighteen pain fellowship programs exist in Canadian MPTFs and 64% engage in some form of research activities CONCLUSION: Canadian MPTFs are unable to meet clinical demands of patients suffering from chronic pain, both in terms of regional accessibility and reasonable wait time for patients' first appointment.  相似文献   
7.
Background: The qualities of visual perception and of motor reaction to the visual stimulus have never been studied in reference to the type of video-camera system (2-D vs 3-D) used during laparoscopy. Methods: The study was designed in two parts. The first evaluated the ability of the eye to discriminate how objects are spaced relative to one another. The second investigated the motor reaction to the visual stimulus in an environment where depth was the preponderent cue. The tests were performed in a pelvi-trainer in which were inserted different modules built either for visual observation (Part 1) or for evaluation of motor ability (Part 2). Variables studied during Part 1 were the time required to do the test and the number of errors committed during its performance. The variable evaluated during Part 2 was the time needed to terminate the test. Each of these two parts of the study were completed alternating the 2-D and 3-D systems. A total of 304 observations were recorded. Statistics used were the paired t-test, the independent group t-test, and the Newman-Keuls multiple comparisons test. Results: Results of Part 1 of the study confirm that visual perception varies significantly among individuals (n = 10) (p < 0.05) and that a true 3-D video-camera system facilitates visual perception when compared to a 2-D system (p < 0.001). Results of Part 2 of the study also show significant differences among participants (n= 9) (p < 0.05). The true 3-D system allowed significantly faster motor performances than the 2-D system (p < 0.001). Conclusion: Our experiment shows that the 3-D system allowed significant improvements in the execution of the evaluated parameters. Also noted were significant differences among participants in term of visual and motor skills.  相似文献   
8.
Abstract: Our group is developing a left ventricular assist device based on the principle of the Maillard-Wankel rotative compressor: it is a rotary, not centrifugal, pump that produces a pulsatile flow. Stringent requirements have been defined for construction materials. They must be light, yet sufficiently hard and rigid, and able to be machined with high precision. The friction coefficient must be low and the wear resistance high. The materials must be chemically inert and not deformable. Also, the materials must be biocompatible, and the blood contacting surface must be hemocompatible. We assessed the materials in terms of physiochemistry, mechanics, and tribology to select the best for hemocompatibility (determined by studies of protein adsorption: platelet, leukocyte, and red cell retention: and hemolysis, among other measurements) and biocompatibility (determined by measurement of complement activation and toxicity, among other criteria). Of the materials tested, for short- and middle-term assistance, we chose titanium alloy (Ti6AI4V) and alumina ceramic (Al2O3) and for long-term and permanent use, composite materials (TiN coating on graphite). We saw that the polishing process of the substrate must be improved. For the future, the best coating material would be diamond-like carbon (DLC) or crystalline diamond coating.  相似文献   
9.
Laser thermal angioplasty is a new technique. The longest follow-up is 3 years. It is used increasingly for the treatment of atheromatous disease of the femoropopliteal segment. The authors describe a case of successful recanalization of a completely occluded left external iliac artery using laser thermal angioplasty. The artery was approached through a left femoral dissection. The patient was discharged from the hospital on postoperative day 4 without claudication. The present indications and potential benefits and complications of this procedure are discussed.  相似文献   
10.
Computed tomographic (CT) renal planimetry was used to study individual renal function in 32 adult patients with urologic disease. CT results were well-correlated to reference methods (r = 0.88, P < 0.001), which were radionuclide studies (N = 9) or separate creatinine clearance (N = 23). The difference between planimetric data and reference methods did not exceed 14% in any case and was less than 10% in 26 cases.  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