首页 | 官方网站   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   1536篇
  免费   70篇
  国内免费   5篇
医药卫生   1611篇
  2023年   11篇
  2021年   42篇
  2020年   17篇
  2019年   24篇
  2018年   25篇
  2017年   19篇
  2016年   18篇
  2015年   30篇
  2014年   44篇
  2013年   47篇
  2012年   69篇
  2011年   82篇
  2010年   62篇
  2009年   45篇
  2008年   63篇
  2007年   99篇
  2006年   75篇
  2005年   86篇
  2004年   72篇
  2003年   61篇
  2002年   64篇
  2001年   49篇
  2000年   49篇
  1999年   45篇
  1998年   11篇
  1997年   12篇
  1996年   15篇
  1995年   10篇
  1994年   15篇
  1993年   7篇
  1992年   30篇
  1991年   23篇
  1990年   32篇
  1989年   19篇
  1988年   26篇
  1987年   19篇
  1986年   20篇
  1985年   22篇
  1984年   14篇
  1983年   16篇
  1982年   9篇
  1981年   7篇
  1980年   7篇
  1979年   10篇
  1976年   8篇
  1974年   10篇
  1972年   10篇
  1971年   8篇
  1970年   9篇
  1968年   7篇
排序方式: 共有1611条查询结果,搜索用时 171 毫秒
101.
BACKGROUND: Cyclosporine monitoring using the 2-hr postdose sample, C2, has been shown to have advantages in monitoring de novo renal transplant recipients. The purpose of this study was to assess cyclosporine exposure, using C2, in stable renal transplant patients previously monitored by C0 to determine the effect of dose reduction on patients with C2 more than 10% above target and the course of those with C2 at and more than 10% below target, whose dose was not modified. METHODS: One hundred and seventy-five patients, three or more months after transplantation, had C2 assessed. The relationship of C2 to C0 and of both to renal function was analyzed by linear regression. Blood pressure, serum creatinine level, and lipids were followed for a mean of 15+/-2.6 months. RESULTS: Eighty-five patients had values more than 10% above target, 42 were within 10% of target, and 48 were more than 10% below target. Cyclosporine dose was reduced in all patients above target. In this group, serum creatinine level was stable overall, but fell significantly in 46 (54%) of 85 from 153+/-55 to 132+/-49 microM. Blood pressure also fell in that group from 135/82 to 131/77. Serum creatinine level was stable in the remaining two groups of patients. CONCLUSIONS: These data suggest that dose reduction in many overexposed patients leads to improvements in renal function and blood pressure. Further study is required to confirm the long-term benefits of this strategy.  相似文献   
102.
103.
BACKGROUND: Transplantation of adult porcine islets (APIs) offers a possible means of treating diabetes. However, isolating APIs has been notoriously difficult. Furthermore, islet xenograft rejection must be prevented. MATERIALS AND METHODS: APIs were isolated by a modified automated method. API quality was assessed by static glucose stimulation (SGS), by transplantation to diabetic nude mice and by intraperitoneal glucose tolerance tests (IPGTTs). The morphologic characteristics of API xenograft rejection in rats were studied immunohistochemically. Furthermore, APIs were transplanted to diabetic rats that were either left untreated or immunosuppressed with cyclosporine A (CsA), mycophenolate mofetil (MMF) and leflunomide (LEF). B-glucose and porcine C-peptide levels were monitored and grafts were studied morphologically. RESULTS: Large numbers of APIs were isolated. At SGS, insulin release increased significantly. All nude mice transplanted with APIs were normoglycemic within 24 hr and remained so for up to 1 year. During IPGTTs, B-glucose levels were rapidly regulated to porcine levels. In untreated rats, API xenografts were destroyed within 6 days by a cellular infiltrate consisting mainly of macrophages. In untreated diabetic rats normoglycemia was sustained for 5.5+/-0.3 days. Rats immunosuppressed with CsA+MMF+LEF remained normoglycemic for 59.6+/-11.3 days. In 3 of 11 rats, normoglycemia was sustained for up to 101 days. Porcine C-peptide was detected in serum. At recurrence of hyperglycemia, many mononuclear cells were found close to the xenografts. However, only occasional cells infiltrated the grafts and many APIs were intact. CONCLUSIONS: Well-functioning APIs can be isolated in large numbers. API xenografts can be protected from rejection and can maintain an adequate function for up to 100 days, in rats immunosuppressed with CsA+MMF+LEF.  相似文献   
104.
Nonlinear dynamics applied to blood pressure control   总被引:1,自引:0,他引:1  
Hypertension is a very frequent disease, known to trigger a range of severe cardiovascular problems. The elucidation of its pathophysiology requires investigation of the mechanisms responsible for the maintenance of blood pressure in the normal system, and their possible failure in hypertension. Some of these control mechanisms display nonlinear features, indicating that the blood pressure signal might be characterized by nonlinear dynamics. Our aim was thus to investigate the nonlinear properties of the blood pressure signal under normal conditions, and in a cardiovascular system prone to hypertension. Blood pressure was investigated in young spontaneously hypertensive rats (SHR), versus their age-matched normotensive progenitors (WKY). The correlation dimension was computed as quantification of blood pressure control complexity. The parameters required for the calculation procedure of the correlation dimension were carefully determined. The results were tested with surrogate data statistics. assuming linear autocorrelated Gaussian noise as the null hypothesis. Non-integer correlation dimension values were found in both strains, with lower values for SHR than for WKY, in particular following alpha-blockade. In all cases, a statistically significant difference was found between the real and surrogate data. These results show that the nonlinear dynamics parameter D, can be used to detect differences in BP control between prehypertensive SHR and WKY rats as early as 6-7 weeks after birth.  相似文献   
105.
STATEMENT OF PROBLEM: The success of dental implant treatment relies on a well-developed treatment plan approach. Historically, implant placement was guided mainly by residual bone height and width, at times compromising prosthetic needs. PURPOSE: This study analyzed the amount of deviation between planned prosthetic trajectory and residual bone trajectory in different areas of the maxillary and mandibular dental arches, by using a tomographic survey in conjunction with imaging/surgical guides. METHODS AND MATERIAL: Ninety-two patients with a total of 235 implant sites were selected for the study. An imaging and surgical guide with a radiopaque indicator was constructed to determine the planned prosthetic trajectory. Cross-sectional tomograms were taken through the indicator at each implant site. The outlines of the available bone, planned prosthetic trajectory, and residual bone trajectory were traced, and the difference in the trajectory between the 2 trajectories was determined. RESULTS: Discrepancies between the planned prosthetic and the residual bone trajectories were greater in the mandibular molar area. This site was statistically different from other site groups at P =.05 (Tukey method). Statistically, all other site groups were not significantly different.  相似文献   
106.
107.
108.
Laser palliation for colorectal carcinoma.   总被引:1,自引:0,他引:1  
N Mandava  N Petrelli  L Herrera  H Nava 《American journal of surgery》1991,162(3):212-4; discussion 215
A review was conducted of 27 patients with colorectal carcinoma treated palliatively with endoscopic neodymium:yttrium-aluminium-garnet (Nd:YAG) laser. There were 25 rectal carcinomas and 2 primary invasive sigmoid colon carcinomas. Of the 25 rectal carcinomas, there was 1 carcinoma in situ, 16 primary cancers, and 8 recurrent rectal carcinomas. The level of the lesions from the anal verge ranged from 0 to 25 cm, with a mean of 7.2 cm. The length of the lesions ranged from 1.5 to 8.5 cm, with a mean of 5 cm. The mean number of Nd:YAG laser treatments was three, with a range from one to nine. The duration of the treatments ranged from 30 to 90 minutes, with a mean of 40 minutes. Four of 27 patients (15%) developed complications. The success rate in terms of the relief of symptoms was established in 23 of the 27 patients.  相似文献   
109.
110.
Regional non-nodal metastases of cutaneous melanoma   总被引:4,自引:0,他引:4  
The authors studied the prognosis of patients with so called local recurrences, satellites and in-transit metastases from cutaneous melanoma on the basis of 291 patients. These are the 19.3% of the 1503 patients with stage I and II melanoma originally submitted to surgical treatment at the National Cancer Institute of Milano (Italy). The majority of patients were males (M/F = 0.7): 102 had local recurrence, 99 in-transit metastases, 24 satellites and 66 both local and in-transit metastases. Regional non-nodal metastases were not related with the site of origin, and inadequate treatment of primary. These metastases were more frequently observed in patients who were submitted to regional node dissection no matter whether in discontinuity or in continuity with primary tumor. The frequency of regional non-nodal metastases was found to increase with increasing thickness of primary melanoma or, in stage II patients, with the number of involved nodes. Local and in-transit metastases were related with prognostic criteria in the same way. The overall survival was very close between in-transit and local metastases. Similar survival rates were observed comparing regional non-nodes and disseminated cutaneous and subcutaneous metastases. The authors conclude that the distinction between local recurrences, satellites and in-transit metastases is artificial and that these metastatic events are not prognostically dissimilar from metastases in distant skin areas.  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-23

京公网安备 11010802026262号