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   1848篇
  免费   140篇
  国内免费   15篇
耳鼻咽喉   14篇
儿科学   40篇
妇产科学   12篇
基础医学   272篇
口腔科学   41篇
临床医学   145篇
内科学   461篇
皮肤病学   25篇
神经病学   107篇
特种医学   62篇
外科学   260篇
综合类   157篇
一般理论   3篇
预防医学   85篇
眼科学   37篇
药学   86篇
中国医学   2篇
肿瘤学   194篇
  2023年   17篇
  2022年   39篇
  2021年   117篇
  2020年   55篇
  2019年   49篇
  2018年   65篇
  2017年   45篇
  2016年   51篇
  2015年   70篇
  2014年   79篇
  2013年   84篇
  2012年   127篇
  2011年   157篇
  2010年   61篇
  2009年   69篇
  2008年   80篇
  2007年   83篇
  2006年   79篇
  2005年   88篇
  2004年   75篇
  2003年   68篇
  2002年   61篇
  2001年   44篇
  2000年   63篇
  1999年   41篇
  1998年   18篇
  1997年   18篇
  1996年   13篇
  1995年   7篇
  1994年   4篇
  1993年   4篇
  1992年   15篇
  1991年   28篇
  1990年   15篇
  1989年   17篇
  1988年   10篇
  1987年   14篇
  1986年   15篇
  1985年   13篇
  1984年   8篇
  1983年   9篇
  1982年   5篇
  1981年   3篇
  1980年   3篇
  1979年   4篇
  1978年   3篇
  1977年   4篇
  1976年   2篇
  1973年   2篇
  1971年   1篇
排序方式: 共有2003条查询结果,搜索用时 15 毫秒
61.
Truly representative architectural parameters of trabeculea can be extremely difficult to achieve based on scanning images because of variable porosity and distribution of trabeculae within the specific overall scanned volume of bone. Accordingly, in present study different selective volume of interests, measured from centroid of μ-CT scanned human vertebral body, were analyzed to determine the architectural parameters (BV/TV, BS/BV, Tb.Th, Tb.N, Tb.Sp) of trabeculae within these volumes and to suggest an optimal volume for representative architectural parameters of the overall scanned volume. Nonlinear curve fitting method was also applied to obtain the correlation between the parameters and the volume of interests. The results show different volumes of interests give different morphological indices of BV/TV, BS/BV, Tb.N and Tb.Sp within a specific scanned vertebral body. Tb.Th shows relatively small variation (0.8%) even with sample volume of less than (2mm)(3). Statistical analysis shows that with sample volume of less than (6mm)(3), significant different in the measured BV/TV comparing against the control group. Tb.N and Tb.Sp show significant different values against the control group for volume of interest less than (4mm)(3) and (5mm)(3), respectively. However, no significant differences were observed in the indices of BS/BV and Tb.Th. Present study shows that an optimal volume of interests of greater than (6mm)(3) be selected to predict the architectural parameters of trabeculae of human vertebral bodies.  相似文献   
62.
AIMS: Periductal angiogenesis in ductal carcinoma in situ is associated with an increased risk of subsequently developing a recurrence. This study aimed to (1) identify the relation between periductal and stromal vascularity and recurrence and (2) determine whether thymidine phosphorylase (TP) is associated with angiogenesis or recurrence in ductal carcinoma in situ (DCIS). METHODS: Twenty cases of DCIS that did not subsequently recur, 20 that developed a subsequent in situ recurrence, and 12 that developed a subsequent invasive recurrence were investigated. Periductal and stromal (hotspot) microvessel density were determined quantitatively using antibodies to CD34 and von Willebrandt factor (vWF). TP expression by DCIS was assessed semiquantitatively using the H score method. RESULTS: Stromal and periductal microvessel density assessed by anti-vWF gave similar mean values, and showed a strong positive correlation. When angiogenesis was assessed with anti-CD34 this association was lost. Not only were the mean values for both types of microvessel density higher than those obtained with anti-vWF, but the periductal microvessel density was significantly greater than the stromal microvessel density. TP expression was associated with stromal microvessel density assessed with anti-vWF, but not with anti-CD34. TP expression was not related to recurrence. No significant difference was identified in TP expression or stromal vascularity in DCIS between cases that recurred as DCIS and those that recurred as invasive carcinoma. CONCLUSIONS: Recurrent in situ or invasive disease after excision of DCIS does not appear to be related to stromal microvessel density or to TP expression by DCIS cells.  相似文献   
63.
BackgroundVancomycin powder and dilute povidone-iodine lavage (VIP) was introduced to reduce the incidence of periprosthetic joint infection (PJI) in high-risk total knee arthroplasty (TKA) patients. We hypothesize that VIP can reduce the incidence of early PJI in all primary TKA patients, regardless of preoperative risk.MethodsAn infection database of primary TKAs performed before a VIP protocol was implemented (January 2012-December 2013), during a time when only high-risk TKAs received VIP (January 2014-December 2015), and when all TKAs received VIP (January 2016-September 2019) at an urban, university-affiliated, not-for-profit orthopedic hospital was retrospectively reviewed to identify patients with PJI. Criteria used for diagnosis of PJI were the National Healthcare Safety Network and Musculoskeletal Infection Society guidelines.ResultsVIP reduced early primary TKA PJI incidence in both the high-risk and all-risk cohorts compared with the pre-VIP cohort by 44.6% and 56.4%, respectively (1.01% vs 0.56% vs 0.44%, P = .0088). In addition, after introducing VIP to all-risk TKA patients, compared with high-risk TKA patients, the relative risk of PJI dropped an additional 21.4%, but this finding did not reach statistical significance (0.56% vs 0.44%, P = .4212). There were no demographic differences between the 3 VIP PJI cohorts.ConclusionVIP is associated with a reduced early PJI incidence after primary TKA, regardless of preoperative risk. With the literature supporting its safety and cost-effectiveness, VIP is a value-based intervention, but given the nature of this historical cohort study, a multicenter randomized controlled trial is underway to definitively confirm its efficacy.  相似文献   
64.
Background  Stress gated myocardial perfusion single photon emission computed tomography (gSPECT) is increasingly used before and after intercurrent therapeutic intervention and is the basis for ongoing evaluation in the Department of Veterans Affairs clinical outcomes utilizing revascularization and aggressive drug evaluation (COURAGE) trial. Methods and Results  The COURAGE trial is a North American multicenter randomized clinical trial that enrolled 2287 patients to aggressive medical therapy vs percutaneous coronary intervention plus aggressive medical therapy. Three COURAGE nuclear substudies have been designed. The goals of substudy 0 are to examine the diagnostic accuracy of the extent and severity of inducible ischemia at baseline in COURAGE patients compared with patient symptoms and quantitative coronary angiography and to explore the relationship between inducible ischemia and the benefit from revascularization when added to medical therapy. Substudy 1 will correlate the extent and severity of provocative ischemia with the frequency, quality, and instability of recurrent symptoms in postcatheterization patients. Substudy 2 (n _ 300) will examine the usefulness of sequential gSPECT monitoring 6 to 18 months after therapeutic intervention. Together, these nuclear substudies will evaluate the role of gSPECT to determine the effectiveness of aggressive risk-factor modifications, lifestyle interventions, and anti-ischemic medical therapies with or without revascularization in reducing patients’ ischemic burdens. Conclusions  The unfolding of evidence on the application of gSPECT in trials such as COURAGE defines a new era for nuclear cardiology. We hope the evidence that emerges from the COURAGE trial will further establish the role of nuclear imaging in the evidence-based management of patients with stable coronary disease. The COURAGE trial was supported by the Cooperative Studies Program of the Department of Veterans Affairs Office of Research and Development in collaboration with the Canadian Institutes of Health Research. Unrestricted research grants were obtained from Merck & Co; Pfizer Pharmaceuticals; Bristol-Myers Squibb Medical Imaging; Astellas Pharma; Kos Pharmaceuticals; Data Scope; Astra Zeneca Pharmaceuticals; Astra-Zeneca-Canada; Schering-Plough Coorporation, Ltd; Sanofi-Aventis, Inc; First Horizon; and GE Healthcare. All industrial funding for this trial was directed through the Department of Veterans Affairs. Additional funding for this substudy was provided by grants to the Department of Veterans Affairs and Canadian Institutes of Health Research from Astellas Pharma and Bristol-Myers-Squibb Medical Imaging.  相似文献   
65.
Objective: Describe demographic characteristics, functional outcomes and disability following rehabilitation for non-ischemic vascular spinal cord dysfunction (SCDys).Design: Retrospective, open cohort, case series.Setting: Tertiary rehabilitation unit, Victoria, Australia.Participants: Patients with non-ischemic vascular SCDys admitted over a 21-year-period (01/01/1995–31/12/2015) were identified using International Classification of Diseases codes.Outcome Measures: Demographic characteristics, etiology, neurologic classification, length of stay (LOS), and complications. On admission and discharge, the following were collected: functional independence measure (FIM) motor subscale, details on bowel, bladder, mobility, living arrangement, and support services.Results: 36 patients (female 58%; mean age 69 ± 16 years) were identified. The main causes of non-ischemic vascular SCDys were epidural hematoma (39%), dural arteriovenous fistula (17%), and arteriovenous malformation (11%). 22 cases (61%) were iatrogenic. Most (86%) had incomplete paraplegia. Urinary tract infection was the most common complication (64%). Median LOS in rehabilitation was 68 days. Significant improvement in FIM motor scores was observed from admission (median 25, interquartile range [IQR] 20–38) to discharge (median 69, IQR 38–77) (P < 0.001). On discharge, 4 patients (11%) walked >100 m unaided, 6 (17%) walked >100 m with assistive device, 10 (28%) walked >10 m with assistive device, 15 (41%) were wheelchair dependent and 1 (3%) patient remained non-mobile. 20 patients (56%) were discharged home, 8 (22%) to nursing home, and 8 (22%) transferred to another hospital.Conclusion: Most patients returned home with significantly improved functional outcomes compared to rehabilitation admission, but with the majority having ongoing major disabilities based on FIM motor scores.  相似文献   
66.

Background

Diabetes is implicated with poorer outcomes and more complications after total knee arthroplasty (TKA). We aim to determine whether diabetes affects infection risk, functional outcomes, patient-reported outcome measures, and patient satisfaction in Asian patients after TKA.

Methods

Prospectively collected data for 905 patients who underwent unilateral TKA by a single surgeon from February 2004 to July 2014 were reviewed, of which 123 (13.6%) patients suffered from diabetes. At 2-year follow-up, the change in range of motion of the operated knee, body mass index, Knee Society Score, Oxford Knee Score (OKS), and Short Form-36 from baseline was compared between diabetic and nondiabetic patients. We also analyzed the length of hospitalization stay, infection risk, and patient satisfaction between the 2 groups.

Results

Compared with nondiabetic patients, diabetic patients had significantly poorer preoperative OKS (37.6 on 8.3 to 35.8 .38.0, P = .02) and Short Form-36 Mental Component Score (48.3 Me11.2 to 51.7 1.10.7, P = .01). At 2-year follow-up, diabetes continued to be associated with poorer OKS of 21.2 018.4 and Knee Society Score Function score of 64.7 Fu20.9 compared to 19.1 0.6.2 (P = .02) and 71.8 0220.1 (P = .01) respectively in nondiabetic patients. Interestingly, the difference in mental well-being was no longer significant after TKA. A significantly larger proportion of diabetic patients (50%) had a reduction in body mass index after TKA compared to 36% in nondiabetic patients (P < .01). There was no difference in range of motion, length of hospitalization stay, infection risk, and patient satisfaction.

Conclusion

Despite poorer physical scores throughout, diabetic patients are no less satisfied and had significantly greater improvement in mental well-being and weight reduction after surgery.  相似文献   
67.
68.
69.

Background

Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) have been shown to improve survival in selected patients with peritoneal carcinomatosis. We review our institutional experience with the procedure and evaluate the overall survival (OS) and disease-free survival (DFS) rates in 100 consecutive patients.

Methods

Data were prospectively collected from 100 consecutive patients with peritoneal carcinomatosis treated by CRS and HIPEC at the National Cancer Centre Singapore between April 2001 and May 2012. Our primary end points were OS and DFS.

Results

Of the 100 patients, 84 were of Chinese ethnicity, 3 were Malay, 6 were Indian, and 7 were of other ethnicities. Primary tumors were ovarian cancer (n = 39), colorectal cancer (n = 28), primary peritoneal (n = 6), appendiceal cancer (n = 20), and mesothelioma (n = 7). Median follow-up duration was 21 months. At 5 years, the DFS was 26.3 % and OS was 50.9 %. Factors influencing OS and DFS were cytoreductive score, primary cancer, and disease-free interval of more than 12 months on univariate analysis. The only factors that remained significant for prognosis after multivariate analysis were primary cancer and cytoreductive score. Thirty-day morbidity was 56 %, and there were no 30-day mortalities.

Conclusions

CRS and HIPEC can be safely carried out in Asian patients with peritoneal carcinomatosis from ovarian, colorectal, appendiceal, mesothelioma, and primary peritoneal origins. Overall, the ovarian, appendiceal, mesothelioma, and primary peritoneal cancer patients tended to do better than the colorectal patients, but careful patient selection ensuring that optimal cytoreduction can be achieved is essential for the success of this procedure.  相似文献   
70.
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