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   4317篇
  免费   485篇
  国内免费   10篇
耳鼻咽喉   33篇
儿科学   113篇
妇产科学   89篇
基础医学   709篇
口腔科学   72篇
临床医学   486篇
内科学   713篇
皮肤病学   100篇
神经病学   293篇
特种医学   339篇
外科学   554篇
综合类   144篇
一般理论   3篇
预防医学   350篇
眼科学   130篇
药学   377篇
中国医学   5篇
肿瘤学   302篇
  2021年   64篇
  2020年   37篇
  2019年   68篇
  2018年   99篇
  2017年   65篇
  2016年   71篇
  2015年   89篇
  2014年   117篇
  2013年   152篇
  2012年   205篇
  2011年   213篇
  2010年   136篇
  2009年   126篇
  2008年   181篇
  2007年   195篇
  2006年   156篇
  2005年   152篇
  2004年   185篇
  2003年   159篇
  2002年   156篇
  2001年   152篇
  2000年   128篇
  1999年   124篇
  1998年   102篇
  1997年   54篇
  1996年   45篇
  1995年   54篇
  1994年   50篇
  1993年   46篇
  1992年   99篇
  1991年   91篇
  1990年   87篇
  1989年   81篇
  1988年   92篇
  1987年   92篇
  1986年   83篇
  1985年   56篇
  1984年   58篇
  1983年   55篇
  1982年   35篇
  1981年   32篇
  1979年   56篇
  1978年   43篇
  1977年   30篇
  1975年   35篇
  1973年   30篇
  1972年   51篇
  1971年   40篇
  1970年   29篇
  1969年   30篇
排序方式: 共有4812条查询结果,搜索用时 15 毫秒
81.
The National Athletic Injury/Illness Reporting System is a national surveillance system created from several workshops at which physicians, athletic trainers, and sports administrators shared their ideas for obtaining meaningful data. The primary objective was to provide a feasible and inexpensive mechanism for the continuous collection and analysis of information on sports-related injuries. Additionally, the project offers institutions and agencies a useful system of recordkeeping. NAIRS collects data on a wide range of sports, however, this report clarifies the risk of injury for high school and college football. Presented are data on neurotrauma, meniscus/knee sprains, and ankle sprains. Playing surface, surface hardness, surface friction, and shoe-turf interface were also examined. It was concluded that no helmet type or brand was associated with unusually high levels of risk. Artificial surfaces did not constitute an additional risk of significant concussion. An association between playing surface and the risk of knee and ankle injuries was observed. J Orthop Sports Phys Ther 1979;1(2):103-108.  相似文献   
82.
83.
84.
BACKGROUND: The demand for renal transplantation has increasingly outstripped the supply of donor organs especially over the past 10 years. Although related and unrelated live donation is being promoted as one option for increasing the donor pool, it is unlikely that this will in itself be able to bridge the gap. Non-heart beating donors (NHBD) can provide an alternative supply of organs, which should substantially increase the donor pool. METHODS: In Newcastle, NHBD kidneys have been used for transplantation for a period of 10 years. In the early period (1988-1993) excellent results were obtained (90.5% success); however, these donors were controlled NHBD, Maastricht category III. In the second phase (1994-1998) increasing numbers of donors were obtained from the Accident and Emergency Department unit. These were failed resuscitation for cardiac arrest (category II). The rates of success in this period were poor (45.5% success) and the program was halted. The third phase of the program used machine perfusion of the kidneys and glutathione S transferase enzyme analysis to assess viability. RESULTS: Using such approaches renal transplants from largely category II donors produced a success rate of 92.3% which was significantly better than the phase II period of the program (P=0.023, Fisher two-tail test). CONCLUSION: Machine perfusion and viability assessment of NHB kidneys in phase III of the program has increased our donor pool as well as improved the graft survival. This is particularly relevant for the use of the category II NHB donor where the incidence of primary nonfunction was high, illustrated by phase II where machine perfusion/viability assessment was not used.  相似文献   
85.
OBJECTIVE: To evaluate radiotherapy dose and length of treatment in the control of early stage nasopharyngeal carcinoma (NPC) treated with a combination of external radiotherapy and brachytherapy, MATERIALS & METHODS: We reviewed the records of 133 patients with early stage nasopharyngeal carcinoma (stage I or II, AJC/UICC staging system) who received definitive radiotherapy in Chang Gung Memorial Hospital from 1979 to 1991. The median follow-up time was 7.1 years with a minimum of 2 years. All patients were treated with megavoltage external radiotherapy to the nasopharynx area (63-72 Gy) followed by high dose rate intracavitary brachytherapy (5-16.5 Gy in one to three fractions, spaced 1-2 weeks apart). The median total dose and time of irradiation was 75 Gy (69.8-81.4 Gy) and 11.6 weeks (7.8-20 weeks) respectively. Survival analysis was used to examine the effect of several variables on prognosis. RESULTS: The 5-year rates were 86.4% for local control, 84.7% for disease free survival, 88.5% for actuarial survival and 84.2% for overall survival. The treatment group (combination of time and dose of irradiation) was the most important prognostic factor according to Cox's proportional hazard model. Patients receiving radiation at a total dose of < or = 75 Gy completed in < 12 weeks showed the best prognosis. CONCLUSION: Treatment time and total treatment dose are both important factors in treating early stage NPC. Decreasing the total radiation time to < 12 weeks and not exceeding a radiation dose of 75 Gy gave the best results.   相似文献   
86.
87.
A self-refrigerated suit using dry ice as cooling agent and allowing the wearer to move about freely is described. Its efficiency during exposure to heat (dry bulb temperature, ta = 46 C; wet bulb temperature, twb = 35 C) and heavy physical work on a treadmill has been demonstrated by experiments on 26 subjects. The heart rate is reduced and the body temperature is decreased. The way in which this self-refrigerated suit reduces the heat load is discussed and the usefulness of its application is emphasized.  相似文献   
88.

Purpose

A prospective, single-center, single-arm feasibility study evaluated procedural and short-term performance of the Advance Enforcer 35 focal-force percutaneous transluminal angioplasty (PTA) balloon catheter in treating stenoses of mature native arteriovenous (AV) hemodialysis access circuits.

Materials and Methods

Twenty-eight patients undergoing treatment for stenosis of a mature native AV hemodialysis access circuit were enrolled at a single institution. Angiographic assessments of the study lesion were required at baseline and after the procedure. Adjunctive procedures for significant residual stenosis were permitted, and patients had clinical and imaging follow-up for as long as 6 months.

Results

Treatment with the study balloon was effective in reducing the average percent diameter stenosis of the treated lesion from 66.3% (range, 43.8%–93.3%) before the procedure to 23.7% (range, ?6.7% to 51.4%) after the procedure. The average inflation pressure required was 12.3 atm. Only 1 patient required an adjunctive procedure, and all patients could resume normal dialysis following the study procedure. At 3 months, 62.0% of study lesions remained patent, and the 6-month patency rate was 25.1%. Two adverse events associated with the study procedure were reported: access-site hematoma and forearm pain (3.6% each).

Conclusions

The results demonstrate safety of the study balloon in treating AV access stenosis. Nominal-diameter angioplasty was achieved at relatively low pressure in most study patients without the use of adjunctive procedures, and resumption of normal dialysis was achieved for all patients.  相似文献   
89.
The purpose was to determine if planned gait termination can identify acute and lingering motor control strategy alterations in post-concussion individuals. Controls completed two standard gait and five planned gait termination trials once while concussed individuals were tested on Day-1 and Day-10 post-concussion. Dependent variables included gait velocity and normalized, relative to standard gait, peak propulsive and braking forces. Control and only Day-1 post-concussion gait velocity differed. Normalized peak propulsive and braking forces were altered on both Day-1 and Day-10. Altered propulsive and braking forces persisted despite all concussion participants achieving their baseline values on standard concussion clinical tests. Thus gait termination can detect both acute and lingering motor control strategy alterations following concussion.  相似文献   
90.
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