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   1609篇
  免费   73篇
  国内免费   3篇
耳鼻咽喉   9篇
儿科学   15篇
妇产科学   69篇
基础医学   124篇
口腔科学   62篇
临床医学   189篇
内科学   246篇
皮肤病学   12篇
神经病学   209篇
特种医学   82篇
外科学   246篇
综合类   4篇
预防医学   124篇
眼科学   16篇
药学   134篇
肿瘤学   144篇
  2023年   10篇
  2022年   4篇
  2021年   32篇
  2020年   30篇
  2019年   43篇
  2018年   42篇
  2017年   29篇
  2016年   38篇
  2015年   38篇
  2014年   52篇
  2013年   83篇
  2012年   139篇
  2011年   113篇
  2010年   77篇
  2009年   70篇
  2008年   111篇
  2007年   117篇
  2006年   105篇
  2005年   74篇
  2004年   88篇
  2003年   61篇
  2002年   60篇
  2001年   16篇
  2000年   9篇
  1999年   15篇
  1998年   10篇
  1997年   15篇
  1996年   7篇
  1995年   8篇
  1994年   15篇
  1993年   8篇
  1992年   6篇
  1991年   10篇
  1990年   12篇
  1989年   5篇
  1988年   8篇
  1987年   7篇
  1986年   4篇
  1985年   11篇
  1984年   12篇
  1983年   10篇
  1982年   20篇
  1981年   12篇
  1980年   6篇
  1976年   5篇
  1971年   6篇
  1970年   4篇
  1969年   3篇
  1968年   5篇
  1967年   5篇
排序方式: 共有1685条查询结果,搜索用时 15 毫秒
1.
BACKGROUND: Common clinical forms of oral lichen planus (OLP) and oral lichenoid reactions (OLR) are erythematous (ERY) or reticular (RET). The purpose of this study was to find histopathological changes that differ between these forms. METHODS: Epithelial thickness, epithelial proliferation rate, apoptosis, and HLA-DR expression were compared among 10 reticular and 12 erythematous lesions, and 11 normal oral mucosa samples (NOM). RESULTS: The epithelium in ERY was thinner than in NOM, whereas RET showed values between ERY and NOM. Cell proliferation increased significantly in ERY as compared with RET and NOM, with no difference between RET and NOM. Relative numbers of epithelial cell nuclei displaying visible chromatin condensation were reduced in ERY form. CONCLUSIONS: The markedly increased cell proliferation in ERY supports the notion that this form displays a higher disease activity as compared to RET. It can therefore be important to study each disease form separately.  相似文献   
2.
Background and Purpose . Patients with multiple sclerosis (MS) tend to have movement difficulties, and the effect of physiotherapy for this group of patients has been subjected to limited systematic research. In the present study physiotherapy based on the Bobath concept, applied to MS patients with balance and gait problems, was evaluated. The ability of different functional tests to demonstrate change was evaluated. Method . A single‐subject experimental study design with ABAA phases was used, and two patients with relapsing–remitting MS in stable phase were treated. Tests were performed 12 times, three at each phase: A (at baseline); B (during treatment); A (immediately after treatment); and A (after two months). The key feature of treatment was facilitation of postural activity and selective control of movement. Several performance and self‐report measures and interviews were used. Results . After intervention, improved balance was shown by the Berg Balance Scale (BBS) in both patients, and improved quality of gait was indicated by the Rivermead Visual Gait Assessment (RVGA). The patients also reported improved balance and gait function in the interviews and scored their condition as ‘much improved’. Gait parameters, recorded by an electronic walkway, changed, but differently in the two patients. Among the physical performance tests the BBS and the RVGA demonstrated the highest change, while no or minimal change was demonstrated by the Rivermead Mobility Index (RMI) and Ratings of Perceived Exertion (RPE). Conclusion . The findings indicate that balance and gait can be improved after physiotherapy based on the Bobath concept, but this should be further evaluated in larger controlled trials of patients with MS. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   
3.
We report the outcome of a femoral stem designed for press-fit insertion and cemented with a thin mantle. During the years 1986–1992 we performed 346 primary total hip replacements in 305 patients. Their mean age at the time of the surgery was 75 (range, 52–91 years). During the follow-up, 206 patients had died (227 hips) and 3 were lost. This left us with 96 patients (116 hips), who were followed for a mean of 13 years (range, 11–18 years). Stem survivorship according to Kaplan–Meier analysis indicated a total survival of 0.982 (confidence intervals, 0.952–1). The mechanical survival rate was 0.985 (confidence intervals, 0.955–1) at 17 years with one patient at risk. Fifty-nine (70%) of the surviving patients were very satisfied with the operated hip, 22 (26%) were satisfied, 2 (2.5%) were content, and 1 (1.5%) was dissatisfied. Then, the press-fit stem allowing minimal cement has a 17-year survival rate of 0.98.  相似文献   
4.
Posterior dislocations of the sternoclavicular joint are uncommon, but are potentially quite serious. Radiologic diagnosis and management are frequently difficult. The specialized projections available are not widely known, and the role of plain films is poorly understood. The incidence, pathomechanics, and clinical manifestations of such dislocations are presented and the radiologic diagnosis is discussed.  相似文献   
5.
A retrospective study was performed on 20 patients with adenoid cystic carcinomas of major salivary glands to see if DNA. patterns correlated with their prognoses. Fourteen tumors were found to be DNA. diploid; 6 were DNA aneuploid. Histologically, all DNA-aneu-ploid tumors had solid components, compared with only 5 of the DNA-diploid tumors. All of the DNA-aneuploid tumors recurred, in contrast to only 2 of the DNA-diploid tumors; the difference was highly significant (P<0.001). All of the patients with no recurrences had DNA-diploid tumors. In our study, DNA measurements of adenoid cystic carcinomas gave statistically significant information about prognosis and correlated to histological grading. We propose that evaluation of DNA content may be performed before planning the treatment of adenoid cystic carcinomas.  相似文献   
6.
Heavy menstrual bleeding is the predominant complaint in women with abnormal uterine bleeding. Treatment options are drug therapy, and first- and second-generation endometrial resection. Many women will subsequently have a hysterectomy. Uterine fibroids are the most common solid pelvic tumours in women, and although many fibroids seem to cause no symptoms, they can have serious adverse effects and impact on quality of life. As women postpone having children, gynaecologists will have to manage fibroids and polyps in a conservative manner. The past decade has witnessed the development of highly sophisticated diagnostic and therapeutic technology for women suffering from menorrhagia, fibroids and polyps, including minimally invasive uterine therapy. The tools currently at our disposal permit greater management flexibility, which must be tailored to the individual clinical situation. This chapter reviews the evidence-based approach and minimally invasive therapy.  相似文献   
7.
A new method for the selective spin labeling of left- or right-sided supplying arteries of the brain without the need for additional RF coils is demonstrated. A clinical 1.5 T scanner was used. The spatial selectivity of the labeling process is based on the limited coverage of the excitation field of a standard send/receive head coil together with an oblique positioning of the labeling plane. A computer simulation was used to optimize key labeling parameters under the condition of laminar flow. The validity of the computer model results was confirmed by MRI measurements with a flow model. For human studies, a double-inversion continuous arterial spin labeling (CASL) sequence was modified to allow for arbitrary positioning of the labeling plane. The obtained perfusion-weighted images showed a clear delineation of the perfusion territories of the selected arteries in the anterior circulation of the brain and good gray/white matter contrast.  相似文献   
8.
As shown in previous studies, the two basic proteins aprotinin (Ap, 6.5 kDa) and cystatin (Cy, 13.3 kDa) can be used to estimate whole kidney glomerular filtration rate by measuring the renal cortical uptake relative to plasma concentration after i.v. injection. Local uptake of Ap can also be used to estimate local filtration rate, and the present experiments were undertaken to examine whether Cy would give a similar uptake pattern. Ap and Cy were labelled with 131I and 125I, respectively, and injected as an i.v. bolus. Frequent blood samples provided information on the filtered load. Five to 20 min after injection the kidney was clamped, frozen, and five tissue samples of 5-10 mg each were cut out from outer (OC), middle (MC) and inner cortex (IC) to be weighed and assessed for radioactivity. Five minute clearance ratios, Cy:Ap, were 1.36 +/- 0.04, 1.27 +/- 0.03 and 1.19 +/- 0.04 in OC, MC and IC, respectively. The higher Cy clearance was expected from a higher glomerular filtrate:plasma ratio of the less basic Cy (Donnan distribution). However, this does not explain the increase of Cy:Ap clearances going from IC to the OC. A surplus of extracellular uptake of Cy in superficial layers was excluded, leading to the following interpretation. In all cortical layers the proximal convoluted tubule, i.e. the protein uptake segment, is located more superficially than its parent glomerulus. A longer uptake segment for Cy than for Ap will therefore lead to a relative greater transfer of filtered Cy from IC to MC, and from MC to OC. Anatomical studies on single nephrons presented in another article lend strong support to this interpretation.  相似文献   
9.
Calculations of normal tissue complication probability (NTCP) values for the rectum are difficult because it is a hollow, non-rigid, organ. Finding the true cumulative dose distribution for a number of treatment fractions requires a CT scan before each treatment fraction. This is labour intensive, and several surrogate distributions have therefore been suggested, such as dose wall histograms, dose surface histograms and histograms for the solid rectum, with and without margins. In this study, a Monte Carlo method is used to investigate the relationships between the cumulative dose distributions based on all treatment fractions and the above-mentioned histograms that are based on one CT scan only, in terms of equivalent uniform dose. Furthermore, the effect of a specific choice of histogram on estimates of the volume parameter of the probit NTCP model was investigated. It was found that the solid rectum and the rectum wall histograms (without margins) gave equivalent uniform doses with an expected value close to the values calculated from the cumulative dose distributions in the rectum wall. With the number of patients available in this study the standard deviations of the estimates of the volume parameter were large, and it was not possible to decide which volume gave the best estimates of the volume parameter, but there were distinct differences in the mean values of the values obtained.  相似文献   
10.
Long-term treatment with pivampicillin and pivmecillinam for 6–24 months in five adults and one child reduced the total serum carnitine concentration to 3.7–14 mol/l (reference value: 25–66 mol/l). Muscle carnitine was reduced to 0.3–0.7mol/g wet weight (reference value: 3–5mol/g) in two cases. All patients had muscle symptoms with weakness, asthenia and pains. One showed signs of carnitine depletion in the liver with increased secretion of dicarboxylic acids (C6, C8, C10) in urine and limited ketone body formation during prolonged fasting. Serum carnitine increased slowly after cessation of therapy and reached normal concentrations after 6–12 months. All symptoms caused by carnitine depletion disappeared. This was achieved on a normal diet without carnitine supplementation.  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