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   14585篇
  免费   1117篇
  国内免费   64篇
耳鼻咽喉   204篇
儿科学   243篇
妇产科学   201篇
基础医学   2235篇
口腔科学   158篇
临床医学   1515篇
内科学   3524篇
皮肤病学   396篇
神经病学   1391篇
特种医学   653篇
外国民族医学   10篇
外科学   2296篇
综合类   40篇
一般理论   5篇
预防医学   639篇
眼科学   195篇
药学   939篇
中国医学   15篇
肿瘤学   1107篇
  2023年   150篇
  2022年   91篇
  2021年   586篇
  2020年   346篇
  2019年   542篇
  2018年   653篇
  2017年   418篇
  2016年   478篇
  2015年   549篇
  2014年   733篇
  2013年   872篇
  2012年   1306篇
  2011年   1295篇
  2010年   701篇
  2009年   631篇
  2008年   973篇
  2007年   940篇
  2006年   809篇
  2005年   756篇
  2004年   648篇
  2003年   547篇
  2002年   482篇
  2001年   113篇
  2000年   107篇
  1999年   88篇
  1998年   69篇
  1997年   50篇
  1996年   51篇
  1995年   58篇
  1994年   44篇
  1993年   43篇
  1992年   58篇
  1991年   65篇
  1990年   56篇
  1989年   51篇
  1988年   36篇
  1987年   37篇
  1986年   34篇
  1985年   20篇
  1984年   26篇
  1983年   31篇
  1982年   34篇
  1981年   14篇
  1980年   15篇
  1979年   18篇
  1978年   16篇
  1977年   12篇
  1974年   14篇
  1972年   13篇
  1968年   10篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Background  A single prospective randomized study found that, in selected patients with acute respiratory failure (ARF) following lung resection, noninvasive ventilation (NIV) decreases the need for endotracheal mechanical ventilation and improves clinical outcome. Method  We prospectively evaluated early NIV use for ARF after lung resection during a 4-year period in the setting of a medical and a surgical ICU of a university hospital. We documented demographics, initial clinical characteristics and clinical outcomes. NIV failure was defined as the need for tracheal intubation. Results  Among 690 patients at risk of severe complications following lung resection, 113 (16.3%) experienced ARF, which was initially supported by NIV in 89 (78.7%), including 59 with hypoxemic ARF (66.3%) and 30 with hypercapnic ARF (33.7%). The overall success rate of NIV was 85.3% (76/89). In-ICU mortality was 6.7% (6/89). The mortality rate following NIV failure was 46.1%. Predictive factors of NIV failure in univariate analysis were age (P = 0.046), previous cardiac comorbidities (P = 0.0075), postoperative pneumonia (P = 0.0016), admission in the surgical ICU (P = 0.034), no initial response to NIV (P < 0.0001) and occurrence of noninfectious complications (P = 0.037). Only two independent factors were significantly associated with NIV failure in multivariate analysis: cardiac comorbidities (odds ratio, 11.5; 95% confidence interval, 1.9–68.3; P = 0.007) and no initial response to NIV (odds ratio, 117.6; 95% confidence interval, 10.6–1305.8; P = 0.0001). Conclusion  This prospective survey confirms the feasibility and efficacy of NIV in ARF following lung resection. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. This work was presented during the September 2008 ESICM congress in Lisbon international meeting and published as an abstract.  相似文献   
92.
93.
94.

Objectives

In this paper, the author proposes to separate delirious melancholy and paranoia, locating in these two psychoses the common points and points which are able to distinguish them clearly.

Methodology

We present the delirious melancholy according to the psychiatrist H. Ey's theory, then – with psychoanalytical approach, according notably to Lacan – we will underline three important points of reference: relationships with “fault”, with the “object”, and finally with the “Other” (Lacan).

Results

These three points will lead us to the melancholic self-accusation and to the paranoiac accusation, to the position of “exception”, and to delirious common themes.

Discussion and conclusion

Finally, we attempt to ascertain – as Freud formulated about paranoiac delirium – whether melancholic delirium could also be a “tentative of (self) cure”.  相似文献   
95.
96.
Huntington''s disease (HD) is caused by cytosine-adenine-guanine (CAG) repeat expansions in the huntingtin (Htt) gene. Although early energy metabolic alterations in HD are likely to contribute to later neurodegenerative processes, the cellular and molecular mechanisms responsible for these metabolic alterations are not well characterized. Using the BACHD mice that express the full-length mutant huntingtin (mHtt) protein with 97 glutamine repeats, we first demonstrated localized in vivo changes in brain glucose use reminiscent of what is observed in premanifest HD carriers. Using biochemical, molecular, and functional analyses on different primary cell culture models from BACHD mice, we observed that mHtt does not directly affect metabolic activity in a cell autonomous manner. However, coculture of neurons with astrocytes from wild-type or BACHD mice identified mutant astrocytes as a source of adverse non-cell autonomous effects on neuron energy metabolism possibly by increasing oxidative stress. These results suggest that astrocyte-to-neuron signaling is involved in early energy metabolic alterations in HD.  相似文献   
97.
Patients with hematological malignancies have a 28-fold increased risk of venous thromboembolism (VTE). Among patients with acute myelogenous leukemia (AML), the 2-year cumulative incidence of VTE is 5.2%. Several studies suggest that microvesicles (MVs) harboring TF may play a role in VTE and disseminated intravascular coagulation (DIC) in acute promyelocytic leukemia (APL).  相似文献   
98.
99.
Background contextSurgical adverse event (AE) monitoring is imprecise, of uncertain validity, and tends toward underreporting. Reports focus on specific procedures rather than outcomes in the context of presenting diagnosis. Specific intraoperative (intraop) or postoperative (postop) AEs that may be independently associated with degenerative spondylolisthesis (DS) have never been reported.PurposeThe primary purpose was to assess the AE profile of surgically treated patients with L4–L5 DS. The secondary goal was to identify potential risk factors that correlate with those AEs.Study design/settingProspective cohort and academic quaternary spine center.Patient sampleNinety-two patients with L4–L5 DS were treated surgically, discharged from Vancouver General Hospital between January 1, 2009 and December 31, 2010.Outcome measuresIncidence rates and odds ratios.MethodsProspective AE data were analyzed using univariate analyses, forward selection regression models, and Spearman correlation coefficients. Results were compared with outcomes reported in the Spine Patient Outcomes Research Trial.ResultsNo AEs were seen in 57.6% of patients, one AE in 17.4%, and two or more AEs in 17.4%. Dural tears (6.5%) and intraop bone-implant interface failure requiring revision (3.3%) were the most common intraop AEs. Postoperatively, the most frequent AEs were urinary tract infection (10.9%), delirium (5.4%), neuropathic pain (4.4%), deep wound infection (3.3%), and superficial wound infection (3.3%). The odds of an intraop AE increased by 9% (95% confidence interval [CI] 1–18) per year of age at admission. Adjusted Charlson comorbidity index (CCI) did not correlate with number of AEs experienced. The odds of postop delirium correlated with CCI (odds ratio [OR] 3.39, 95% CI 1.12–10.24) and dural tear (OR 35.84, 95% CI 1.72–747.45). Length of stay was statistically significant and was influenced by two or more AEs, CCI, postop loss of correction, cerebrospinal fluid leak, deep wound infection, noninfected wound drainage, and gender.ConclusionsRisk of intraop AEs, but not postop AEs, increased with increasing age. Having multiple comorbidities does not predispose to more AEs. Infections predominate among the postop AEs. Patients at increased risk of delirium or of having an increased length of hospital stay may more easily be predicted. Studies specifically designed to prospectively assess AEs have the potential to more accurately identify postop AE rates.  相似文献   
100.

Introduction

It is a well-established dogma that many surgeons do not reach a quintessential level of their technical operative skills until successful completion of their training program. The aim of this study was to test the hypothesis that early introduction of supervised residents to non-complex spinal surgical procedures within a structured and supervised educational program does not harm the patient in terms of higher complication rates or worse pain- and health-related quality of life (HrQOL) outcomes.

Methods

A prospective study on 102 patients undergoing surgery for lumbar disc herniation (LDH) was performed. The procedures were dichotomized into two groups according to the surgeon’s level of experience: teaching cases (neurosurgical residents in the 1st to 4th year of training) and non-teaching cases (experienced board-certified faculty neurosurgeons). Pain levels (VAS) and the HrQOL using the 12-item short-form health survey (SF-12) were measured at baseline, at 4 weeks and as a survey at 1 year postoperatively. In addition, data concerning the operation and the postoperative course including common complications were assessed.

Results

Intraoperative blood loss, length of surgery, as well as intra- and postoperative complications were similar between the study groups. Patients in both groups achieved equal results in terms of pain reduction after 4 weeks [mean VAS change ?3.8 (teaching cases) vs. ?3.1 (non-teaching cases), p?=?0.25] and 1 year postoperatively [mean change in VAS ?3.5 (teaching cases) vs. ?3.37 (non-teaching cases), p?=?0.84]. Teaching cases were 100 % (odds ratio of 1.00) as likely as non-teaching cases to achieve a favorable HrQOL response to surgery (p?=?0.99).

Conclusions

Early introduction of resident surgeons to lumbar microdiscectomy can be conducted safely within a structured and supervised educational program as it neither harms the patient nor leads to worse 1-year results. Surgical resident education may thus be implemented safely in times of rigorous working laws. However, a structured education program in which the senior surgeon gives advice, guidance and communicates cautions during each resident surgery is of paramount importance to provide high-quality patient care.  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