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   11829篇
  免费   784篇
  国内免费   23篇
耳鼻咽喉   75篇
儿科学   417篇
妇产科学   232篇
基础医学   1382篇
口腔科学   156篇
临床医学   1296篇
内科学   1996篇
皮肤病学   148篇
神经病学   1546篇
特种医学   546篇
外科学   2009篇
综合类   122篇
一般理论   22篇
预防医学   1137篇
眼科学   108篇
药学   823篇
中国医学   24篇
肿瘤学   597篇
  2023年   62篇
  2022年   90篇
  2021年   245篇
  2020年   163篇
  2019年   271篇
  2018年   309篇
  2017年   209篇
  2016年   252篇
  2015年   240篇
  2014年   427篇
  2013年   586篇
  2012年   902篇
  2011年   952篇
  2010年   528篇
  2009年   484篇
  2008年   831篇
  2007年   797篇
  2006年   782篇
  2005年   825篇
  2004年   752篇
  2003年   716篇
  2002年   651篇
  2001年   99篇
  2000年   67篇
  1999年   89篇
  1998年   140篇
  1997年   102篇
  1996年   104篇
  1995年   90篇
  1994年   71篇
  1993年   54篇
  1992年   58篇
  1991年   45篇
  1990年   33篇
  1989年   39篇
  1988年   57篇
  1987年   40篇
  1986年   36篇
  1985年   29篇
  1984年   44篇
  1983年   45篇
  1982年   47篇
  1981年   33篇
  1980年   48篇
  1979年   26篇
  1978年   20篇
  1977年   19篇
  1976年   21篇
  1972年   14篇
  1971年   14篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
141.
142.
PURPOSE: To investigate the therapeutic impact of chemotherapy-induced amenorrhea in premenopausal patients with breast cancer. PATIENTS AND METHODS: We conducted a retrospective cohort study of a National Cancer Institute of Canada Clinical Trials Group phase III trial involving premenopausal patients randomized to receive cyclophosphamide, methotrexate, and fluorouracil (CMF), versus intensive cyclophosphamide, epirubicin, and fluorouracil (CEF). The objectives of our study were to describe the incidence of amenorrhea at 6 and 12 months post-random assignment and to determine the association of amenorrhea with relapse-free and overall survival. RESULTS: Data on 442 patients were used in our analyses. Despite the higher cumulative dose of cyclophosphamide in the CMF treatment arm, at 6 months post-random assignment, the rate of amenorrhea was higher in the CEF group (relative risk, 1.2; 95% CI, 1.0 to 1.3), with no difference at 12 months. In the receptor-positive subgroup, 6-month amenorrhea rates were not associated with prognosis. In contrast, amenorrhea at 12 months was significantly associated with relapse-free survival (hazard ratio, 0.51; 95% CI, 0.32 to 0.82; P = .005) and overall survival (hazard ratio, 0.40; 95% CI, 0.22 to 0.72; P = .002). CONCLUSION: Late chemotherapy-induced amenorrhea seems to be associated with improved outcome in patients with premenopausal, receptor-positive breast cancer.  相似文献   
143.
High utilizers of alcohol and other drug treatment (AODTx) services are a priority for healthcare cost control. We examine characteristics of Medicaid-funded AODTx clients, comparing three groups: individuals < 90th percentile of AODTx expenditures (n = 41,054); high-cost clients in the top decile of AODTx expenditures (HC; n = 5,718); and 1760 enrollees in a chronic care management (CM) program for HC clients implemented in 22 counties in New York State. Medicaid and state AODTx registry databases were combined to draw demographic, clinical, social needs and treatment history data. HC clients accounted for 49% of AODTx costs funded by Medicaid. As expected, HC clients had significant social welfare needs, comorbid medical and psychiatric conditions, and use of inpatient services. The CM program was successful in enrolling some high-needs, high-cost clients but faced barriers to reaching the most costly and disengaged individuals.  相似文献   
144.
Objectives. To describe the work factors associated with 28 different career areas as reported by pharmacists who responded to the American Pharmacists Association (APhA) Career Pathway Evaluation Program for Pharmacy Professionals, 2012 Pharmacist Profile SurveyMethods. Data from the 1,119 completed survey instruments from the 2012 Pharmacist Profile Survey were analyzed. Exploratory factor analysis was used to identify the underlying factors that best represented respondents’ work setting profiles.Results. Eleven underlying factors were identified for the respondents’ work setting profiles: patient care, application of clinical knowledge, innovation, stress, research, managerial responsibility, work schedule flexibility, job position flexibility, self-actualization, geographic location, and continuity of coworker relationships. Findings revealed variation for these underlying factors among career categories.Conclusion. Variation among pharmacist career types exists. The profiles constructed in this study describe the characteristics of various career paths and can be helpful for decisions regarding educational, experiential, residency, and certification training in pharmacist careers.  相似文献   
145.
146.
147.
Young [1649 population doubling level (PDL)] and senescing (50–53 PDL) WI-38 cell populations were exposed to 1 ppm ozone for 2 hr and the resultant extracellular and intracellular acid phosphatase concentration was measured. Dose response curves were also determined for surviving populations of young and old cells after a 1 hr ozone exposure ranging in concentration from 0 to 1.00 ppm. Senescing cells released 8 times more acid phosphatase per million cells than the young cells. Both old and young cells showed a clear dose-response to the 1 hr ozone gradient exposure. However, the older cells demonstrated a consistent 17% average lower survival rate than the young cells. The higher acid hydrolase level in older WI–38 cells is probably related to the lower survival rate observed in the older cells in vitro.  相似文献   
148.
ObjectThe use of transpedicular screw fixation has been widely accepted for the treatment of degenerative and traumatic pathology of the lumbar spine. Complications of spinal instrumentation can be serious. Screw misplacement can result in unintended durotomy, nerve root and/or cauda equina injury. In comparison to fluoroscopy-assisted screw placement, computer-assisted image guidance has been shown to achieve overall higher rates of accuracy. The O-arm is able to obtain computed tomography (CT)-type images with multiplanar reconstruction. In this study we evaluated a cohort of patients who underwent posterior lumbar fusion with pedicle screws utilizing the O-arm imaging system.MethodsA retrospective review of 40 consecutive patients who underwent posterior lumbar fusion surgery with O-arm utilization, was performed. The study population included 14 males and 26 females. Age range was 39-85 years with an average of 63.8 years. Twenty one patients had degenerative lumbar stenosis (52.5%) and 19 had spondylolisthesis (47.5%). Intraoperative CT-images were obtained. The mean time for surgery and screw placement was assessed.ResultsA total of 252 pedicle screws were sited using O-arm navigation system, with a mean of 6.3 screws per patient (range 4-10). On the basis of intraoperative CT, 3 screws were redirected, representing a 98.81% accuracy rate.The mean duration of surgery was 157.2 (90-240) minutes and the mean time for screw placement was 7.13 (3.08-15) minutes per screw.Three patients (7.5%) developed superficial wound infections which were treated conservatively. No patients required a return to the operating room because of screw malposition.ConclusionThe use of intraoperative O-arm imaging system with computer-assisted navigation significantly increases the surgical accuracy and safety of pedicle screw placement in lumbar fusion surgery.  相似文献   
149.
150.
Background: Hyperkyphosis is associated with physical impairments, activity limitations, and reduced quality of life. Therefore, a simple, reliable, responsive, and valid clinical measure of dorsal kyphosis would be valuable to clinicians. Objective: To describe a novel procedure for measuring kyphotic curvature—the inclinometric kyphosis measure (IKM)—and provide an estimation of reliability, responsiveness, and validity. Methods: During 2 sessions spaced days apart, we used a bubble inclinometer to measure dorsal kyphosis in 68 patients receiving outpatient physical therapy. We also documented occiput-to-wall status and tragus-to-wall distance. Results: Intra-rater reliability of the IKM was supported by intra-class correlation coefficients (ICC3,1) of 0.94 and 0.91 for relaxed and cued conditions, respectively. Responsiveness, as indicated by minimal detectable change, was 8.0 and 10.0 degrees under relaxed and cued conditions, respectively. Validity was supported by significant correlations between the IKM and tragus-to-wall and by differences in the IKM between: 1) relaxed and cued conditions; 2) patients who could and could not touch occiput to the wall; and 3) patients who were older versus younger than 50 years of age. Conclusions: The IKM is a simple, reliable, responsive, and valid method for assessing posture in patients with musculoskeletal conditions.  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