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   128581篇
  免费   7461篇
  国内免费   726篇
耳鼻咽喉   1304篇
儿科学   4117篇
妇产科学   2901篇
基础医学   18555篇
口腔科学   5500篇
临床医学   11822篇
内科学   28310篇
皮肤病学   3072篇
神经病学   12518篇
特种医学   2946篇
外国民族医学   1篇
外科学   11683篇
综合类   527篇
一般理论   63篇
预防医学   13364篇
眼科学   1973篇
药学   8812篇
中国医学   552篇
肿瘤学   8748篇
  2024年   129篇
  2023年   1183篇
  2022年   2618篇
  2021年   4348篇
  2020年   2760篇
  2019年   3703篇
  2018年   4263篇
  2017年   3255篇
  2016年   3677篇
  2015年   4124篇
  2014年   5381篇
  2013年   6985篇
  2012年   10559篇
  2011年   11119篇
  2010年   6010篇
  2009年   5030篇
  2008年   8754篇
  2007年   8759篇
  2006年   8018篇
  2005年   7460篇
  2004年   6700篇
  2003年   5964篇
  2002年   5360篇
  2001年   839篇
  2000年   660篇
  1999年   845篇
  1998年   955篇
  1997年   776篇
  1996年   658篇
  1995年   567篇
  1994年   536篇
  1993年   423篇
  1992年   407篇
  1991年   311篇
  1990年   279篇
  1989年   275篇
  1988年   247篇
  1987年   208篇
  1986年   221篇
  1985年   178篇
  1984年   185篇
  1983年   204篇
  1982年   218篇
  1981年   171篇
  1980年   187篇
  1979年   112篇
  1978年   115篇
  1977年   104篇
  1976年   82篇
  1974年   74篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.

Purpose

Evidence suggests that young adults experiencing homelessness (YEH) are at elevated risk of HIV compared to housed youth. Given the limited research on pre-exposure prophylaxis (PrEP) awareness among YEH, this study examined their PrEP knowledge and attitudes.

Methods

Data from a cross-sectional survey among YEH (ages 18–26) (n?=?1,427) in seven U.S. cities were used to assess their knowledge and attitudes regarding PrEP to inform HIV prevention efforts.

Results

Participants were primarily male youth of color. The mean age was 20.9years. While 66% felt at risk for HIV, only 14% strongly agreed that they try to protect themselves from getting infected with HIV. Most (84%) were eligible for PrEP based on risk, yet only 29% had knowledge of PrEP. Despite this, 59% reported they were likely/extremely likely to take PrEP. Access to free PrEP (55%), HIV testing (72%), healthcare (68%), and one-on-one (62%), and text messaging support (57%) were rated as very/extremely important for PrEP uptake and adherence.

Conclusions

The results of this study suggest missed opportunities to prevent new HIV infections among YEH. Efforts to increase PrEP uptake among this population should consider provider- and system-level interventions to increase PrEP awareness, decrease PrEP-associated healthcare costs, improve access to PrEP providers, and provide in-person and text messaging support.  相似文献   
972.
973.
Aims: To review existing evidence on effectiveness of community-based diversion programmes for Class A drug-using offenders.

Methods: 31 databases were searched for studies published 1985–2012 (update search 2012–2016) involving community-based Criminal Justice System diversion of Class A drug users via voluntary or court-mandated treatment.

Findings: 16 studies were initially included (US, 10; UK, 4; Canada, 1; Australia, 1). There was evidence for a small impact of diversion to treatment on drug use reduction (primary Class A drug use: OR 1.68, CI 1.12–2.53; other drug use: OR 2.60, 1.70–3.98). Class A drug users were less likely to complete treatment (OR 0.90, 0.87–0.94) than users of other drugs. There was uncertainty surrounding results for offending, which were not pooled due to lack of outcome measure comparability and heterogeneity. Individual studies pointed to a minor effect of diversion on offending. Findings remained unchanged following an update review (evidence up to March 2016: US, 3; Australia, 1).

Conclusions: Treatment accessed via community-based diversion is effective at reducing drug use in Class A drug-using offenders. Evidence of a reduction in offending amongst this group as a result of diversion is uncertain. Poor methodological quality and data largely limited to US methamphetamine users limits available evidence.  相似文献   

974.
ObjetivoEl objetivo del estudio es describir la percepción de la calidad de vida relacionada con la salud de personas con depresión y comorbilidad física bajo una perspectiva de género. Se incluyeron 380 individuos mayores de 49 años con, al menos, una patología de las siguientes: diabetes, enfermedad obstructiva pulmonar crónica y cardiopatía isquémica, reclutadas en 31 equipos de atención primaria de Cataluña. La calidad de vida se midió con la escala EuroQol (EQ-5D). Además, se recogieron variables sociodemográficas, gravedad de depresión, índice de privación económica y ámbito de residencia. Se evaluó la relación ajustada entre el sexo y las dimensiones de calidad de vida, mediante una regresión logística multivariante.ResultadosEl 81,3% fueron mujeres; la media de edad fue de 68,4 años (DE: 8,8), La media de la escala visual analógica fue de 57,8 (DE: 17,4) en hombres y 55,8 (DE: 18,6) en mujeres. La media del EQ-Health Index fue de 0,74 (DE: 0,17) en hombres y 0,65 (DE: 0,21) en mujeres (p = 0,001). La probabilidad de presentar problemas en las dimensiones del EQ-5D mostró el sexo como factor de más peso (mujer = 1/hombre = 0) en: autocuidado OR: 2,29 (IC 95% 1,04 a 5,07) y actividades cotidianas OR: 3,09 (IC 95% 1,67 a 5,71). La movilidad se asoció con la edad OR: 1,87 (IC 95% 1,22 a 2,86), el ámbito de residencia con el dolor OR: 2,51 (IC 95% 1,18 a 5,34) y el Beck Depression Inventory (BDI) con la ansiedad/depresión OR: 4,77 (IC 95% 1,77 a 12,88).ConclusiónLa percepción en la calidad de vida de las mujeres con depresión y comorbilidad física es inferior a la de los hombres, siendo en ambos casos inferior a la de población general.Palabras clave: Calidad de vida, Depresión, Comorbilidad física, Género, Atención Primaria  相似文献   
975.
976.
Objective: To provide clinicians and researchers information regarding (1) the existing outcome measures to assess the loss of functionality in the activities of daily living (ADLs) of patients with stroke and (2) the presence of these assessment tools in the Italian context.

Study Design and Setting: For this Systematic Review Medline, CINAHL, and PsycINFO were searched for articles published up to 4 July 2017. Two authors independently identified eligible studies on the basis of prede?ned inclusion criteria and extracted data. Study quality and risk of bias were assessed using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies.

Results: Of 370 publications identified and screened, 46 studies fell within the inclusion criteria and were critically reviewed. The most commonly used tools were: the Frenchay Activities Index and the Functional Independence Measure.

Conclusion: This review has emphasized the need for agreement among researchers as to which tool must be studied in depth or adapted to other national contexts in order to develop universal norms and standards.  相似文献   

977.
Background: In the last few years, there has been increasing demand for aesthetic procedures to improve the effects of skin aging.

Aim: To evaluate the anti-aging efficacy, tolerability and skin changes induced by the topical products containing hyaluronic acid, N-acetyl glucosamine and gamma-amino butyric acid through instrumental techniques, clinical and subjective evaluation.

Patients/Method: Twenty female enrolled applied a day and night cream after applying a serum, once week applied a mask, for 2 months. A clinical assessment of smoothness, expression wrinkles, fine wrinkles and measurements of the parameters using Reveal Imager, X-Rite, Corneometer, Dermalab, Moisture Meter EpiD were taken at day 0, 15, 30 and 60 of study period. A final assessment questionnaire was submitted.

Results: The products were accepted by all the volunteers. The hydration (Corneometer: T0 49.17 vs T60 61.11, average variation 24.28%) (Moisture Meter EpiD: T0 45.73 vs T60 61.10, average variation 33.60%), elasticity (Dermalab: T0 56.06 vs T60 62.78, average variation 11.98%) and lightening of the skin (X-Rite: T0 60.23 vs T60 63.36, average variation 5.26%) improved. All changes were statistically significant (p < 0.05).

Conclusion: The efficacy of the topical products is confirmed by subjective, clinical and instrumental assessment. This should be a routine approach in dermatologic practice.  相似文献   

978.
Background and purpose — 1 in 5 patients are dissatisfied following unicompartmental or total knee arthroplasty (UKA or TKA). This may be partly explained by failing to return to desired activity post-arthroplasty. To facilitate return to desired activity, a greater understanding of predictors of return to desired activity in UKA and TKA patients is needed. We compared rates of return to desired activity 12 months following UKA vs. TKA, and identified and compared predictors of return to desired activity 12 months following UKA vs. TKA.

Patients and methods — Patients were prospectively recruited from 2 hospitals prior to undergoing UKA or primary TKA. Patients reported preoperatively the activity/activities that were limited due to their knee that they wished to return to after arthroplasty. At 12-months postoperatively, patients reported whether they had returned to these activities (‘return to desired activity’). Preoperative predictors evaluated were age, sex, BMI, education, comorbidities, pain expectations, Oxford Knee Score (OKS), UCLA Activity Score, and EQ-5D. Generalized linear models assessed the relationship between potential predictors and return-to-desired-activity.

Results — The response rate of all patients eligible for 12-month follow-up was 74%. TKA patients (n = 575) were older (mean (SD) 70 (9) vs. 67 (10)) with a greater BMI (31 (6) vs. 30 (5)) than patients undergoing UKA (n = 420). 75% of UKA and 59% of TKA patients returned to desired activity. TKA patients had a greater risk of non-return to desired activity than patients undergoing UKA (risk ratio (95% CI) 1.5 (1.2–1.8)). Predictors of non-return to desired activity following UKA were worse OKS (0.96 (0.93–0.99)), higher BMI (1.04 (1.01–1.08)), and worse expectations (1.9 (1.2–2.8)). Predictors of non-return to desired activity following TKA were worse EQ-5D (0.53 (0.33–0.85)) and worse OKS (0.98 (0.96–1.0)).

Interpretation — UKA patients were more likely to return to desired activity than TKA patients. Predictors of return to desired activity differed following UKA and TKA. Optimizing selection of arthroplasty procedure based on patient characteristics and targeting predictors of poor outcome may facilitate return to desired activity with potential to enhance postoperative satisfaction.  相似文献   

979.

Introduction

The objective of this study was to present the outcomes of moderately hypofractionated helical intensity-modulated radiation therapy (HT) with/without simultaneous integrated boost (SIB) on fluorodeoxyglucose-positron emission tomography (FDG-PET) positive areas (gross tumor volume [GTV]-PET) for patients with progressive malignant pleural mesothelioma (MPM) after previous treatments.

Methods and Materials

From May 2006 to April 2014, 51 patients with a median age of 68.8 years (range, 38.6-82 years) were treated. There were 41 men and 10 women; 43 epithelioid MPM and 8 sarcomatoid, involving the left pleura in 25 patients and the right pleura in 26 patients. The initial stage was: I, 11 patients; II, 14 patients; III, 17 patients; and IV, 9 patients. Chemotherapy was prescribed for 46 patients, for 6 cycles (range, 0-18 cycles). Eighteen patients had pleurectomy/decortication, and 33 had talc pleurodesis. FDG-PET was used for target identification. A median dose of 56 Gy/25 fractions was prescribed to the involved pleura, and SIB to 62.5 Gy to GTV-PET was added in 38 patients.

Results

The median survival from diagnosis was 25.8 months (range, 8.4-99.0 months). One patient, treated with SIB, was alive at the October 2017 follow-up. Two cases of grade 5 radiation pneumonitis were registered. A GTV-PET ≤ 205 cc was predictive of late ≥ grade 2 lung toxicity, but also of better survival in stage III and IV disease: 5.9 versus 11.7 months (P = .04). A GTV-PET ≥ 473 cc was predictive of early death (P = .001).

Conclusions

Moderately hypofractionated, FDG-PET guided salvage HT in patients with progressive MPM after previous treatments showed acceptable toxicity and outcome results similar to adjuvant radiotherapy after pleurectomy/decortication, suggesting that the delay of radiotherapy is not detrimental to survival, and has the associated benefit of postponing inherent toxicity.  相似文献   
980.
Context  Congenital generalized lipodystrophy, or Berardinelli–Seip syndrome, is a rare autosomal recessive disease caused by mutations in either the BSCL2 or AGPAT2 genes. This syndrome is characterized by an almost complete loss of adipose tissue usually diagnosed at birth or early infancy resulting in apparent muscle hypertrophy. Common clinical features are acanthosis nigricans, hepatomegaly with or without splenomegaly and high stature. Acromegaloid features, cardiomyopathy and mental retardation can also be present.
Design  We investigated 11 kindreds from different geographical areas of Brazil (northeast and southeast). All coding regions as well as flanking intronic regions of both genes were examined. Polymerase chain reaction (PCR) amplifications were performed using primers described previously and PCR products were sequenced directly.
Results  Four AGPAT2 and two BSCL2 families harboured the same set of mutations. BSCL2 gene mutations were found in the homozygous form in four kindreds (c.412C>T c.464T>C, c.518–519insA, IVS5-2A>G), and in two kindreds compound mutations were found (c.1363C>T, c.424A>G). In the other four families, one mutation of the AGPAT2 gene was found (IVS3-1G>C and c.299G>A).
Conclusions  We have demonstrated four novel mutations of the BSCL2 and AGPAT2 genes responsible for Berardinelli–Seip syndrome and Brunzell syndrome (AGPAT2-related syndrome).  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