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   38507篇
  免费   2628篇
  国内免费   140篇
耳鼻咽喉   582篇
儿科学   1026篇
妇产科学   1068篇
基础医学   6075篇
口腔科学   752篇
临床医学   3770篇
内科学   7411篇
皮肤病学   869篇
神经病学   3692篇
特种医学   1810篇
外国民族医学   9篇
外科学   5369篇
综合类   367篇
一般理论   61篇
预防医学   2844篇
眼科学   947篇
药学   2610篇
中国医学   74篇
肿瘤学   1939篇
  2021年   577篇
  2020年   353篇
  2019年   540篇
  2018年   664篇
  2017年   538篇
  2016年   679篇
  2015年   724篇
  2014年   911篇
  2013年   1365篇
  2012年   1912篇
  2011年   2148篇
  2010年   1150篇
  2009年   1048篇
  2008年   1775篇
  2007年   1911篇
  2006年   1849篇
  2005年   1833篇
  2004年   1807篇
  2003年   1674篇
  2002年   1709篇
  2001年   944篇
  2000年   826篇
  1999年   822篇
  1998年   492篇
  1997年   414篇
  1996年   358篇
  1995年   344篇
  1994年   311篇
  1993年   298篇
  1992年   483篇
  1991年   458篇
  1990年   487篇
  1989年   459篇
  1988年   425篇
  1987年   471篇
  1986年   419篇
  1985年   430篇
  1984年   365篇
  1983年   294篇
  1982年   298篇
  1981年   244篇
  1980年   263篇
  1979年   322篇
  1978年   284篇
  1977年   254篇
  1976年   219篇
  1974年   259篇
  1973年   239篇
  1972年   261篇
  1971年   225篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Cognitive Therapy and Research - Despite interest in psychological inflexibility as a marker of suicide risk, no measure of psychological inflexibility specific to SI exists. The present study...  相似文献   
2.
3.
TL1A is a TNF‐like cytokine which has been shown to co‐stimulate TH1 and TH17 responses during chronic inflammation. The expression of this novel cytokine has been investigated in inflammatory disorders like rheumatoid arthritis and inflammatory bowel disease, but little is known about expression and induction in psoriasis. Indeed, the pathogenesis in psoriasis is still not fully understood and it is speculated that cytokines other than TNF‐α are important in subsets of patients. Also, for patients with severe disease that are treated with systemic anti‐TNF‐α blockade, novel candidates to be used as disease and response biomarkers are of high interest. Here, we demonstrate TL1A expression in biopsies from psoriatic lesions. Also, we investigated spontaneous and induced TL1A secretion from PBMCs and blood levels from a cohort of psoriasis patients. Here, increased spontaneous secretion from PBMCs was observed as compared to healthy controls and a small subset of patients had highly elevated TL1A in the blood. Interestingly, activation of PBMCs with various cytokines showed a decreased sensitivity for TL1A activation in psoriasis patients compared to healthy controls.TL1A levels in blood and biopsies could not be correlated with disease activity with this patient cohort. Thus, additional large‐scale studies are warranted to investigate TL1A as a biomarker.  相似文献   
4.
5.
6.
7.
Hyperhidrosis can seriously impair patients’ quality of life. Medical history, including heredity and hyperhidrosis during youth, as well as current age and time elapsed since menopause, is important to consider when distinguishing between postmenopausal hyperhidrosis and vasomotor symptoms to enable adequate treatment. This report concerns a subgroup of eight postmenopausal patients participating in a randomized controlled trial regarding botulinum toxin (Btx) type B treatment in craniofacial hyperhidrosis. Even though the sample size is small and the enrolment is not yet completed, the promising data collected hitherto are interesting to present in advance because this subtype of craniofacial hyperhidrosis is often underrecognized and challenging to treat. Patients were randomized to receive Btx type B or placebo. Measurements were performed before treatment and 3 ± 1 weeks after. The Dermatology Life Quality Index (DLQI) score was improved for all patients after Btx type B treatment (n = 3) with a median decrease of 9 points (90% median improvement). The placebo group (n = 5) had a median increase of 2 points (–18% median decline). When the same group (n = 5) received Btx type B (open) the DLQI score decreased with a median of 7 points compared with baseline (91% median improvement). Treatment‐related adverse events were temporary and did not prevent improvement of life quality. Furthermore, background data evaluation uncovered interesting findings regarding vasomotor symptoms in relation to postmenopausal hyperhidrosis. In conclusion, the results indicated that Btx type B seems to be a safe and effective treatment in postmenopausal craniofacial hyperhidrosis. Further research is encouraged.  相似文献   
8.

Background Context

The concept of dynamic stabilization (DS) of the lumbar spine for treatment of degenerative instability has been introduced almost two decades ago. Dynamic stabilization follows the principle of controlling movement in the coronal plane by providing load transfer of the spinal segment without fusion and, at the same time, reducing side effects such as adjacent segment disease (ASD). So far, only little is known about revision rates after DS due to ASD and screw loosening (SL).

Purpose

The present study aimed to evaluate the longitudinal revision rates following dynamic pedicle screw stabilization in the lumbar spine and to determine specific risk factors predictive for ASD, SL, and overall reoperation in a large cohort with considerable follow-up.

Design

We carried out a post hoc analysis of a prospectively collected database in a level I spine center.

Patients Example

The patient sample comprised 283 (151 female/132 male) consecutive patients suffering from painful degenerative lumbar segmental instability with or without spinal stenosis who underwent DS of the lumbar spine (Ulrich Cosmic, Ulrich Medical, Ulm, Germany) between January 2008 and December 2011.

Outcome Measures

Longitudinal reoperation rate and risk factors predictive for revision surgery were evaluated.

Methods

We analyzed the longitudinal reoperation rate due to ASD and SL and overall reoperation. Risk factors such as age, gender, body mass index, lumbar lordosis (LL), number of segments, and number of previous surgeries were taken into account. Regular and mixed model logistic regressions were performed to determine risk factors for revision surgery on a patient and on a screw level.

Results

The mean age was 65.7±10.2 years (range 31–88). One hundred thirty-two patients were stabilized in 1 segment, 134 in 2 segments, 15 in 3 segments, and 2 patients in 4 segments. Reoperation rate for ASD and SL after 1 year was 7.4 %, after 2 years was 15.0%, and after a mean follow-up of 51.4±15 months was 22.6%. Reasons for revision were SL in 19 cases (6.6%), ASD in 39 cases (13.7%), SL and ASD in 6 cases, hematoma in 2 cases (0.7%), cerebrospinal fluid fistulae in 3 cases (1.1%), infection in 6 cases (2.1%), and implant failure in 1 case (0.4%). The patients' age, the number of stabilized segments, and the number of previous surgeries and postoperative LL had a significant influence on the probability for revision surgery.

Conclusions

Reoperation rates after DS of the lumbar spine are comparable with rigid fixations. The younger the patient and the more segments are involved, the lower the LL and the more previous surgeries were found, the higher was the risk of revision. Risk of revision was almost twice as high in men compared with women. We therefore conclude that for clear clinical indication and careful evaluation of preoperative imaging data, DS using the Cosmic system seems to be a possible option. The presented data will help to further tailor indication and patient selection.  相似文献   
9.
10.

Background

Physicians treating nonvalvular atrial fibrillation (AF) assess stroke and bleeding risks when deciding on anticoagulation. The agreement between empirical and physician-estimated risks is unclear. Furthermore, the association between patient and physician sex and anticoagulation decision-making is uncertain.

Methods

We pooled data from 2 national primary care physician chart audit databases of patients with AF (Facilitating Review and Education to Optimize Stroke Prevention in Atrial Fibrillation and Coordinated National Network to Engage Physicians in the Care and Treatment of Patients with Atrial Fibrillation Chart Audit) with a combined 1035 physicians (133 female, 902 male) and 10,927 patients (4567 female and 6360 male).

Results

Male physicians underestimated stroke risk in female patients and overestimated risk in male patients. Female physicians estimated stroke risk well in female patients but underestimated the risk in male patients. Risk of bleeding was underestimated in all. Despite differences in risk assessment by physician and patient sex, > 90% of patients received anticoagulation across all subgroups. There was modest agreement between physician estimated and calculated (ie, CHADS2 score) stroke risk: Kappa scores were 0.41 (0.35-0.47) for female physicians and 0.34 (0.32-0.36) for male physicians.

Conclusions

Our study is the first to examine the association between patient and physician sex influences and stroke and bleeding risk estimation in AF. Although there were differences in agreement between physician estimated stroke risk and calculated CHADS2 scores, these differences were small and unlikely to affect clinical practice; further, despite any perceived differences in the accuracy of risk assessment by sex, most patients received anticoagulation.  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