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   4239篇
  免费   334篇
  国内免费   31篇
耳鼻咽喉   37篇
儿科学   180篇
妇产科学   43篇
基础医学   663篇
口腔科学   136篇
临床医学   456篇
内科学   921篇
皮肤病学   250篇
神经病学   233篇
特种医学   324篇
外科学   474篇
综合类   145篇
一般理论   1篇
预防医学   261篇
眼科学   43篇
药学   302篇
中国医学   2篇
肿瘤学   133篇
  2018年   54篇
  2017年   52篇
  2016年   59篇
  2015年   74篇
  2014年   84篇
  2013年   139篇
  2012年   122篇
  2011年   117篇
  2010年   94篇
  2009年   76篇
  2008年   79篇
  2007年   126篇
  2006年   127篇
  2005年   112篇
  2004年   111篇
  2003年   108篇
  2002年   106篇
  2001年   85篇
  2000年   89篇
  1999年   96篇
  1998年   101篇
  1997年   117篇
  1996年   117篇
  1995年   82篇
  1994年   89篇
  1993年   88篇
  1992年   70篇
  1991年   84篇
  1990年   90篇
  1989年   99篇
  1988年   85篇
  1987年   80篇
  1986年   87篇
  1985年   77篇
  1984年   80篇
  1983年   49篇
  1981年   47篇
  1980年   67篇
  1979年   54篇
  1978年   51篇
  1977年   57篇
  1976年   54篇
  1972年   56篇
  1971年   45篇
  1965年   57篇
  1964年   59篇
  1963年   58篇
  1962年   46篇
  1961年   46篇
  1960年   71篇
排序方式: 共有4604条查询结果,搜索用时 305 毫秒
1.
2.
BackgroundA venous leg ulcer is a chronic leg wound caused by poor venous blood circulation in the lower limbs. It is a recurring condition causing pain, malodour, reduced mobility, and depression. Randomised controlled trials evaluating treatments for venous leg ulcers provide important evidence to inform clinical decision-making. However, for findings to be useful, outcomes need to be clinically meaningful, consistently reported across trials, and fully reported. Research has identified the large number of outcomes reported in venous leg ulcer trials, impacting both synthesis of results, and clinical decision-making. To address this, a core outcome set will be developed. A core outcome set is an agreed standardised set of outcomes which should be, as a minimum, measured and reported in all trials which evaluate treatment effectiveness for a given indication. A core outcome set has the potential to reduce research waste, improve the utility of RCTs, reduce reporting bias, facilitate treatment comparisons across different sources of evidence and expedite the production of systematic reviews, meta-analyses and evidence-based clinical guidelines.AimThe aim of this project is to develop a core outcome set for research evaluating the effectiveness of interventions for treating venous leg ulceration.MethodsThrough a scoping review of the literature on venous leg ulceration, we will firstly identify a list of candidate outcome domains (broad categories in relation to what is being measured) from randomised controlled trials and qualitative research, and outcomes (specific methods in relation to what is being measured). In two further stages, we will use the resulting lists of outcome domains and outcomes to design two online surveys. A range of stakeholders will be invited to participate in the surveys and they will be asked to indicate which outcome domains and outcomes are most important and should be considered as core in future research reports.  相似文献   
3.
A series of three World Café events centred on the topic of developing an Educational Framework for Urological Nursing [EFUN] were held by the British Association of Urological Nurses [BAUN], the European Association of Urology Nurses [EAUN] and the Australian and New Zealand Urological Nursing Society [ANZUNS] between 2017 and 2019. About 376 urology nurses participated in these “conversations that matter” and generated 1047 individual response items that were grouped into themes to assist the three associations to take the creation of an EFUN to the next level. Areas explored centred on four aspects: what any agreed educational framework for urology nursing should contain; the academic level at which education should be provided; who should be recruited as collaborators on writing an educational framework and, lastly, just how any emergent framework should be used. Analysis of the conversational data indicate that there exists within the urological nursing community a collective wisdom regarding their educational needs and how these needs should be met.  相似文献   
4.
MATTHEW  B.  COLLIER  C.  ANDERSON  ENGH  JR.  JAMES  P.  MCAULEY  STUART  D.  GINN  GERARD  A.  ENGH  蔡迅梓 《骨科动态》2006,2(2):93-99
背景:从关节和胫骨假体聚乙烯衬垫后表面转移磨损碎屑,是全膝关节置换术后假体周围骨溶解的主要原因。全膝人工关节假体设计随时问而发生变化,例如对胫骨盘近端表面的粗糙度和聚乙烯衬垫的灭菌方法。我们假设胫骨盘表面抛光和采用空气中γ射线照射之外的其他方法对衬垫灭菌,可降低骨溶解的发生率。方法:从1987年至1998年,我们采用后十字韧带保留型的解剖型组配式全膝人工关节假体系列。对300名患者施行365例全膝关节置换术。术后5至10年,对这些患者的膝关节摄正、侧位X线片。由两位关节置换专家对X线片上的骨溶解状况进行单独评定(骨溶解的界定标准为假体周围存在边缘清晰的非线性松质骨丢失区)。结果:在粗糙表面的胫骨盘的242例膝关节中,使用空气中γ射线照射灭菌的衬垫固定,有34%(82例)骨溶解阳性。用惰性气体中γ射线照射或没有照射的衬垫与抛光表面连接的98例膝关节中,有9%(9例)骨溶解阳性。骨溶解与六项因素相关,这些因素为:一项与患者(男性)相关、一项与胫骨盘(近端表面抛光)相关、三项与聚乙烯衬垫(加工的原材料、灭菌方法及存放时间)相关及一项与手术技术(股骨假体与胫骨假体间的过伸)相关。结论:在这类假体设计中,胫骨盘近端表面采用抛光及衬垫采用更为先进的灭菌方法(不用空气中γ射线照射灭菌)能显著减少骨溶解的发生率,但不能避免骨溶解。  相似文献   
5.
6.
Haaga  JR; Beale  SM 《Radiology》1986,161(3):829-830
By injecting small amounts of CO2 through a needle, one can move bowel or bladder from the intended path of instruments during interventional procedures. The technique worked well in six of seven cases in the pelvis and retroperitoneum; it was not effective in the mediastinum or midabdomen (n = 6).  相似文献   
7.
This study evaluates the potential for endothelial seeding of a collagen-impregnated Dacron graft with or without surface modifiers (fibronectin, heparin) to attach and retain these cells during flow. Human umbilical endothelial cells were harvested, cultured, labeled with Indium111-oxine and seeded onto 30 mm X 4 mm diameter grafts. Six graft surfaces were studied: 1) a collagen-impregnated Dacron graft, HemashieldR (C); 2) C + fibronectin (C + F); 3) C + heparin (C + H); 4) C + F + H; 5) HytrelR + F (Hyt + F); and 6) Hyt + F + H. Radioactive loss determined the percentage attachment and then percentage retention of labeled inoculum after a one-hour in vitro perfusion. Scanning electron and light microscopy demonstrated the endothelium on the graft surface following perfusion. Fibronectin-coated grafts had a significantly higher percentage attachment than those without fibronectin (ANOVA, P less than 0.05). However, the percentage retention following perfusion was similar for all Dacron grafts and statistically inferior to the HytrelR grafts studied (ANOVA, P less than 0.05). SEM evaluation of the C + F + H graft surface was qualitatively the most impressive Dacron surface for seeding, yet was inferior to the HytrelR graft. We conclude that fibronectin benefits the initial attachment of endothelium to collagen-coated Dacron rivaling the HytrelR surface. Fibronectin does not improve percentage retention of the HemashieldR surface during perfusion, therefore, some of its initial benefit is lost.  相似文献   
8.
Primary tuberculous pathology in nasolpolypi is a rare condition. A case of bilateral ethmoidal polypi with tubercular lesion diagnosed on histopathologlcal examination is being reported and the available relevant literature has been reviewed.  相似文献   
9.
The purpose of the study was to compare an interview measure of quality of object relations to questionnaire and interview measures of recent interpersonal functioning with respect to the prediction of therapeutic alliance and psychotherapy outcome. The sample consisted of 64 patients who had received approximately 20 sessions of short-term individual psychotherapy within a controlled, clinical-trial investigation. Ratings of therapeutic alliance were provided independently by the patient and the therapist after each session. Outcome measures, which were provided by three sources (patient, therapist, and independent assessor), covered the areas of interpersonal functioning, psychiatric symptomatology, self-esteem, and life satisfaction. Quality of object relations, which characterizes the patient's lifelong pattern of relationships, was the best predictor. It was significantly related to patient-rated and therapist-rated therapeutic alliance and to patient improvement of both general symptomatology and specific target problems. The study also replicated previous studies that have reported significant relationships between therapeutic alliance and therapy outcome. The advantages of pretherapy predictors of therapy outcome, such as quality of object relations, are discussed.  相似文献   
10.
A Dose-Response Analysis of Methoxychlor-Induced Alterationsof Reproductive Development and Function in the Rat. GRAY, L.E., JR., OSTBY, J., FERRELL, J., REHNBERG, G., LINDER, R., COOPER,R., GOLDMAN, J., SLOTT, V., AND LASKEY, J. (1989). Fundam. Appl.Toxicol12, 92–108. In the present study rats were dosed fromweaning, through puberty and gestation, to Day 15 of lactationwith methoxychlor at 25, 50, 100, or 200 mg/kg/day. Morphologicallandmarks of puberty were measured, including the ages at vaginalopening, first estrus, and first estrous cycle in females andat preputial separation in males. In the female, estrous cyclicity,fertility, litter size, number of implantation sites, organweights, and ovarian and uterine histology were also measured.The viability of the offspring (F1) and their fertility wereevaluated using a continuous breeding protocol. Males were necropsiedafter breeding, the reproductive organs were weighed, and thecauda epididymal sperm counts were determined. One testis wasused for histopathology, while the other was used to quantifyinterstitial fluid (IF) content, IF testosterone concentration,and testicular sperm production. Testosterone and an drogen-bindingprotein were measured in the caput epididymis, and sperm motilityand morphology were evaluated from a caudal sample. The serumand pituitary were saved for hormonal determinations. Methoxychloraccelerated the age at vaginal opening and first estrus, andthe vaginal smears were cornified. Growth was retarded at 100and 200 mg/kg/day and fertility was reduced when the femaleswere bred with untreated or similarly treated males. In thehighest- dose group, the mated females went from constant estrusinto pseudopregnancy following mating, but they had no implants.In males, methoxychlor treatment markedly reduced growth, seminalvesicle weight, cauda epididymal weight, caudal sperm content,and pituitary weight. Puberty was delayed in the two highest-dosagegroups. Testicular sperm measures were much less affected thancaudal measures. Testis weight and histology were slightly affected,and testicular sperm production, sperm morphology, and motilitywere unaffected. Endocrine function of the testes and pituitarywas altered by methoxychlor administration. Leydig cell testosteroneproduction, in response to human chorionic gonadotropin challenge,was reduced and pituitary levels of prolactin, thyroid-stimulatinghormone (TSH), and follicle-stimulating hormone (FSH) were altered.In contrast, serum levels of prolactin, FSH, and luteinizinghormone were unaffected. Serum TSH was reduced by 50% of controlat 100 and 200 mg/kg/day, while pituitary levels were increased.Gonadotropin-releasing hormone concentration in the mediobasalhypothalamus was also elevated. In spite of the many reproductivealterations, the fertility of treated males was not reducedwhen they were mated with untreated females. Growth and viabilityof the offspring (F1) from the 50 mg/kg/day treatment groupwere normal, but in the females, vaginal opening was accelerated,estrous cyclicity was abnormal in the rats during middle age,and fecundity was reduced.  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