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   2529篇
  免费   411篇
  国内免费   30篇
耳鼻咽喉   20篇
儿科学   92篇
妇产科学   79篇
基础医学   320篇
口腔科学   77篇
临床医学   280篇
内科学   433篇
皮肤病学   49篇
神经病学   154篇
特种医学   293篇
外科学   224篇
综合类   170篇
一般理论   4篇
预防医学   214篇
眼科学   177篇
药学   229篇
中国医学   3篇
肿瘤学   152篇
  2021年   36篇
  2019年   34篇
  2018年   36篇
  2017年   23篇
  2016年   30篇
  2015年   33篇
  2014年   60篇
  2013年   57篇
  2012年   65篇
  2011年   88篇
  2010年   71篇
  2009年   46篇
  2008年   73篇
  2007年   101篇
  2006年   71篇
  2005年   71篇
  2004年   69篇
  2003年   88篇
  2002年   62篇
  2001年   46篇
  2000年   80篇
  1999年   68篇
  1998年   84篇
  1997年   95篇
  1996年   99篇
  1995年   65篇
  1994年   67篇
  1993年   57篇
  1992年   58篇
  1991年   61篇
  1990年   62篇
  1989年   87篇
  1988年   91篇
  1987年   73篇
  1986年   82篇
  1985年   75篇
  1984年   37篇
  1983年   40篇
  1982年   39篇
  1981年   28篇
  1980年   34篇
  1979年   50篇
  1978年   35篇
  1977年   42篇
  1976年   57篇
  1975年   33篇
  1974年   28篇
  1972年   25篇
  1970年   23篇
  1969年   18篇
排序方式: 共有2970条查询结果,搜索用时 15 毫秒
81.

Introduction

Fast track methodology or enhanced recovery schemes have gained increasing popularity in perioperative care. While evidence is strong for colorectal surgery, its importance in gastric and oesophageal surgery has yet to be established. This article reviews the evidence of enhanced recovery schemes on outcome for this type of surgery.

Methods

A systematic literature search was conducted up to March 2014. Studies were retrieved and analysed using predetermined criteria.

Results

From 34 articles reviewed, 18 eligible studies were identified: 7 on gastric and 11 on oesophageal resection. Three randomised controlled trials, five case-controlled studies and ten case series were identified. The reported protocols included changes to each stage of the patient journey from pre to postoperative care. The specific focus following oesophageal resections was on early mobilisation, a reduction in intensive care unit stay, early drain removal and early (or no) contrast swallow studies. Following gastric resections, the emphasis was on reducing epidural anaesthesia along with re-establishing oral intake in the first three postoperative days and early removal of nasogastric tubes.In the papers reviewed, mortality rates following fast track surgery were 0.8% (9/1,075) for oesophageal resection and 0% (0/329) for gastric resection. The reported morbidity rate was 16.5% (54/329) following gastric resection and 38.6% (396/1,075) following oesophageal resection. Length of stay was reduced in both groups compared with conventional recovery groups in comparative studies.

Conclusions

The evidence for enhanced recovery schemes following gastric and oesophageal resection is weak, with only three (low volume) published randomised controlled trials. However, the enhanced recovery approach appears safe and may be associated with a reduction in length of stay.  相似文献   
82.
Mimuro  J; Schleef  RR; Loskutoff  DJ 《Blood》1987,70(3):721-728
The extracellular matrix (ECM) of cultured bovine aortic endothelial cells (BAEs) was analyzed by immunoblotting and reverse fibrin autography and shown to contain type 1 plasminogen activator inhibitor (PAI-1). Most PAI-1 in the ECM formed complexes with exogenously added tissue-type plasminogen activator (tPA), demonstrating that this PAI-1 was functionally active. The resulting tPA/PAI-1 complexes were recovered in the reaction solution, indicating that the PAI-1 in such complexes no longer bound to ECM. The PAI-1 could not be removed by incubating ECM in high salt (2 mol/L NaCl), sugars (1 mol/L galactose, 1 mol/L mannose), glycosaminoglycans (10 mmol/L heparin, 10 mmol/L dermatan sulfate), or epsilon-aminocaproic acid (0.1 mol/L). However, PAI-1 could be extracted from ECM by treatment with either arginine (0.5 mol/L) or potassium thiocyanate (2 mol/L), or by incubation under acidic conditions (pH 2.5). ECM depleted of PAI-1 by acid extraction was able to bind both the active and latent forms of PAI-1. In this instance, most of the bound PAI-1 did not form complexes with tPA, indicating that the latent form was not activated as a consequence of binding to ECM. Although the PAI-1 activity in conditioned medium decayed with a half-life (t 1/2) of less than 3 hours, the t 1/2 of ECM- associated PAI-1 was greater than 24 hours. These data suggest that PAI- 1 is produced by cultured BAEs in an active form and is then either released into the medium where it is rapidly inactivated or into the subendothelium where it binds to ECM. The specific binding of PAI-1 to ECM protects it from this inactivation.  相似文献   
83.
Eosinophils stimulate fibroblast DNA synthesis   总被引:9,自引:0,他引:9  
Pincus  SH; Ramesh  KS; Wyler  DJ 《Blood》1987,70(2):572-574
Fibrosis complicates a number of chronic inflammatory diseases and occurs in some conditions following chronic hypereosinophilic syndromes. We assessed whether eosinophils might be a source of fibrogenic factors. Extracts of human and guinea pig cell populations enriched for eosinophils contained substances that stimulated tritiated thymidine incorporation by human fibroblasts. Supernatants derived from resting eosinophils and extracts prepared from eosinophil granules also contained fibrogenic factors. Our findings demonstrate a new potential role for eosinophils and suggest a causal relationship between tissue eosinophilia and scar formation in certain parasitic conditions.  相似文献   
84.
85.

Background

Fractures of the capitellum are rare injuries, and few studies have reported the results of fragment excision.

Questions/Purposes

The purpose of this study was to determine range of motion and short-term clinical outcomes for patients treated with capitellum excision.

Methods

A retrospective review was performed to identify all patients with an isolated capitellum fracture who underwent excision as definitive treatment at our institutions. Mechanism of injury, associated elbow injuries, type of capitellum fracture, complications, and postoperative outcomes including final elbow range of motion (ROM), elbow instability, and Disabilities of the Arm, Shoulder and Hand (DASH) score were recorded.

Results

Four patients met the inclusion and exclusion criteria of this study. All patients were female with an average age of 69 years (range 42–85). Based on the Bryan and Morrey classification system, three (75%) fractures were classified as type I and one (25%) fracture as type III. The average clinical follow-up was 11 months. Final examination demonstrated a mean elbow range of motion from 14° (range 0–30) of extension to 143° (range 130–160) of flexion. All patients had full forearm rotation, and there was no clinical evidence of elbow instability. The average DASH score was 18.3 (12.5–24.2) at final follow-up.

Conclusion

Excision of the capitellum, much like excision of the radial head, results in acceptable short-term outcome scores and elbow range of motion in patients with fractures that are not amenable to open reduction and internal fixation.

Electronic supplementary material

The online version of this article (doi:10.1007/s11420-015-9452-x) contains supplementary material, which is available to authorized users.  相似文献   
86.
87.
Acne vulgaris     
Williams HC  Dellavalle RP  Garner S 《Lancet》2012,379(9813):361-372
Acne is a chronic inflammatory disease of the pilosebaceous unit resulting from androgen-induced increased sebum production, altered keratinisation, inflammation, and bacterial colonisation of hair follicles on the face, neck, chest, and back by Propionibacterium acnes. Although early colonisation with P acnes and family history might have important roles in the disease, exactly what triggers acne and how treatment affects the course of the disease remain unclear. Other factors such as diet have been implicated, but not proven. Facial scarring due to acne affects up to 20% of teenagers. Acne can persist into adulthood, with detrimental effects on self-esteem. There is no ideal treatment for acne, although a suitable regimen for reducing lesions can be found for most patients. Good quality evidence on comparative effectiveness of common topical and systemic acne therapies is scarce. Topical therapies including benzoyl peroxide, retinoids, and antibiotics when used in combination usually improve control of mild to moderate acne. Treatment with combined oral contraceptives can help women with acne. Patients with more severe inflammatory acne usually need oral antibiotics combined with topical benzoyl peroxide to decrease antibiotic-resistant organisms. Oral isotretinoin is the most effective therapy and is used early in severe disease, although its use is limited by teratogenicity and other side-effects. Availability, adverse effects, and cost, limit the use of photodynamic therapy. New research is needed into the therapeutic comparative effectiveness and safety of the many products available, and to better understand the natural history, subtypes, and triggers of acne.  相似文献   
88.
Oral Diseases (2012) 19 , 46–58 Sjögren’s syndrome (SjS) is one of the most common autoimmune rheumatic diseases, clinically characterized by xerostomia and keratoconjunctivitis sicca. We investigated the following controversial topics: (i) Do we have reliable ways of assessing saliva production? (ii) How important are the quantity and quality of saliva? (iii) Are only anti‐SSA/Ro and anti‐SSB/La relevant for the diagnosis of SjS? (iv) Are the American‐European Consensus criteria (AECC) the best way to diagnose SjS? Results from literature searches suggested the following: (i) Despite the fact that numerous tests are available to assess salivation rates, direct comparisons among them are scarce with little evidence to suggest one best test. (ii) Recent developments highlight the importance of investigating the composition of saliva. However, more research is needed to standardize the methods of analysis and collection and refine the quality of the accumulating data. (iii) In addition to anti‐Ro/La autoantibodies, anti α‐fodrin IgA and anti‐MR3 autoantibodies seem to be promising diagnostic markers of SjS, but more studies are warranted to test their sensitivity and specificity. (iv) AECC are classification, not diagnostic criteria. Moreover, recent innovations have not been incorporated into these criteria. Consequently, treatment directed to patients diagnosed using the AECC might exclude a significant proportion of patients with SjS.  相似文献   
89.
90.

Introduction

The high mortality and morbidity associated with resection for oesophagogastric malignancy has resulted in a conservative approach to the postoperative management of this patient group. In August 2009 we introduced an enhanced recovery after surgery (ERAS) pathway tailored to patients undergoing resection for oesophagogastric malignancy. We aimed to assess the impact of this change in practice on standard clinical outcomes.

Methods

Two cohorts were studied of patients undergoing resection for oesophagogastric malignancy before (August 2008 – July 2009) and after (August 2009 – July 2010) the implementation of the ERAS pathway. Data were collected on demographics, interventions, length of stay, morbidity and in-hospital mortality.

Results

There were 53 and 55 oesophagogastric resections undertaken respectively for malignant disease in each of the study periods. The median length of stay for both gastric and oesophageal resection decreased from 15 to 11 days (Mann– Whitney U, p<0.001) following implementation of the ERAS pathway. There was no significant increase in morbidity (gastric resection 23.1% vs 5.3% and oesophageal resection 25.9% vs 16.7%) or mortality (gastric resection no deaths and oesophageal resection 1.8% vs 3.6%) associated with the changes. There was a significant decrease in the number of oral contrast studies used following oesophageal resection, with a reduction from 21 (77.8%) in 2008–2009 to 6 (16.7%) in 2009–2010 (chi-squared test, p<0.0001).

Conclusions

The introduction of an enhanced recovery programme following oesophagogastric surgery resulted in a significant decrease in length of median patient stay in hospital without a significant increase in associated morbidity and mortality.  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