全文获取类型
收费全文 | 1036篇 |
免费 | 89篇 |
国内免费 | 19篇 |
专业分类
儿科学 | 77篇 |
妇产科学 | 4篇 |
基础医学 | 128篇 |
口腔科学 | 63篇 |
临床医学 | 119篇 |
内科学 | 180篇 |
皮肤病学 | 46篇 |
神经病学 | 27篇 |
特种医学 | 241篇 |
外科学 | 77篇 |
综合类 | 29篇 |
预防医学 | 48篇 |
眼科学 | 13篇 |
药学 | 29篇 |
1篇 | |
肿瘤学 | 62篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 5篇 |
2020年 | 9篇 |
2019年 | 8篇 |
2018年 | 14篇 |
2017年 | 6篇 |
2016年 | 12篇 |
2015年 | 27篇 |
2014年 | 23篇 |
2013年 | 41篇 |
2012年 | 22篇 |
2011年 | 20篇 |
2010年 | 53篇 |
2009年 | 52篇 |
2008年 | 22篇 |
2007年 | 33篇 |
2006年 | 23篇 |
2005年 | 25篇 |
2004年 | 15篇 |
2003年 | 26篇 |
2002年 | 18篇 |
2001年 | 15篇 |
2000年 | 5篇 |
1999年 | 22篇 |
1998年 | 81篇 |
1997年 | 76篇 |
1996年 | 59篇 |
1995年 | 52篇 |
1994年 | 37篇 |
1993年 | 45篇 |
1992年 | 7篇 |
1991年 | 23篇 |
1990年 | 14篇 |
1989年 | 42篇 |
1988年 | 35篇 |
1987年 | 25篇 |
1986年 | 18篇 |
1985年 | 18篇 |
1984年 | 9篇 |
1983年 | 12篇 |
1982年 | 14篇 |
1981年 | 14篇 |
1980年 | 15篇 |
1979年 | 3篇 |
1978年 | 13篇 |
1977年 | 11篇 |
1976年 | 10篇 |
1975年 | 8篇 |
1954年 | 1篇 |
排序方式: 共有1144条查询结果,搜索用时 15 毫秒
91.
92.
93.
H Boralessa DR Goldhill K Tucker AJ Mortimer J Grant-Casey 《Annals of the Royal College of Surgeons of England》2009,91(7):599-605
INTRODUCTION
Blood is a scarce and expensive product. Although it may be life-saving, in recent years there has been an increased emphasis on the potential hazards of transfusion as well as evidence supporting the use of lower transfusion thresholds. Orthopaedic surgery accounts for some 10% of transfused red blood cells and evidence suggests that there is considerable variation in transfusion practice.PATIENTS AND METHODS
NHS Blood and Transplant, in collaboration with the Royal College of Physicians, undertook a national audit on transfusion practice. Each hospital was asked to provide information relating to 40 consecutive patients undergoing elective, primary unilateral total hip replacement surgery. The results were compared to indicators and standards.RESULTS
Information was analysed relating to 7465 operations performed in 223 hospitals. Almost all hospitals had a system for referring abnormal pre-operative blood results to a doctor and 73% performed a group-and-save rather than a cross-match before surgery. Of hospitals, 47% had a transfusion policy. In 73%, the policy recommended a transfusion threshold at a haemoglobin concentration of 8 g/dl or less. There was a wide variation in transfusion rate among hospitals. Of patients, 15% had a haemoglobin concentration less than 12 g/dl recorded in the 28 days before surgery and 57% of these patients were transfused compared to 20% with higher pre-operative values. Of those who were transfused, 7% were given a single unit and 67% two units. Of patients transfused two or more units during days 1–14 after surgery, 65% had a post transfusion haemoglobin concentration of 10 g/dl or more.CONCLUSIONS
Pre-operative anaemia, lack of availability of transfusion protocols and use of different thresholds for transfusion may have contributed to the wide variation in transfusion rate. Effective measures to identify and correct pre-operative anaemia may decrease the need for transfusion. A consistent, evidence-based, transfusion threshold should be used and transfusion of more than one unit should only be given if essential to maintain haemoglobin concentrations above this threshold. 相似文献94.
Christine AE Schutgens Merel Schuring Toon AJ Voorham Alex Burdorf 《BMC public health》2009,9(1):197-11
Background
The relationship between poor health and unemployment is well established. Health promotion among unemployed persons may improve their health. The aims of this study were to investigate characteristics of non-participants and drop-outs in a multidisciplinary health promotion programme for long-term unemployed persons with health complaints, to evaluate changes in physical health among participants, and to investigate determinants of improvement in physical health. 相似文献95.
96.
97.
98.
Expression of bcl-xL can confer a multidrug resistance phenotype 总被引:14,自引:3,他引:14
It has been suggested that genes that regulate apoptotic cell death may play an important role in determining the sensitivity of tumor cells to chemotherapy. We have recently cloned a member of the bcl-2 family, bcl- x. To test whether bcl-XL expression affects the sensitivity of tumor cells to chemotherapy, we have created stable cell lines overexpressing bcl-XL and have tested these cells for resistance to cell death induced by metabolic inhibitors and chemotherapeutic agents. Bcl-XL expression dramatically reduces the cytotoxicity of bleomycin, cisplatin, etoposide, vincristine, hygromycin B, and mycophenolic acid for up to 4 days in culture. Bcl-XL does not prevent cells from undergoing cell cycle arrest in response to these drugs, but rather prevents treated cells from undergoing apoptosis. Cell-cycle analysis on cells treated with the chemotherapeutic agents bleomycin, cisplatin, etoposide, and vincristine, show that the drugs cause growth arrest in different positions within the cell cycle. Bcl-XL expressing cells treated with chemotherapeutic drugs retain their proliferative ability after the drugs are removed. Interestingly, vincristine-treated cells expressing bcl-XL become polyploid after drug removal. These data show that bcl-XL protects cells from a wide variety of apoptotic stimuli, acts in multiple positions within the cell cycle, and confers a multidrug resistance phenotype. The ability of bcl-XL to prevent apoptotic cell death in response to chemotherapy-induced DNA damage and cell-cycle arrest may contribute to the accumulation of chromosomal aberrations within tumors. The expression of bcl-XL in tumor cells is likely to be an important indicator of chemotherapeutic efficacy. 相似文献
99.
Antonina A Mikocka-Walus Deborah A Turnbull Jane M Andrews Nicole T Moulding Ian G Wilson Hugh AJ Harley David J Hetzel Gerald J Holtmann 《Clin Pract Epidemiol Ment Health》2008,4(1):15
Background
In independent studies, IBD, IBS and HCV have each been associated with a substantially increased risk of psychological problems such as depression and anxiety and impairment of quality of life compared to the general healthy population. However, the relative psychological burden for each of these diagnoses is unknown as it has never been compared contemporaneously at one institution. Current local data are therefore needed to enable an evidence-based allocation of limited clinical psychological resources.Methods
Overall, 139 outpatients (64 IBD, 41 HCV, and 34 IBS) were enrolled in this cross-sectional study. The HADS, SCL90, SF-12 and appropriate disease-specific activity measures were administered. Differences between groups were assesed with ANOVA, the Chi-Square test and the independent samples t-test (two-tailed).Results
Each of the three groups had significantly lower quality of life than the general population (p < 0.05). Overall, a total of 58 (42%) participants met HADS screening criteria for anxiety and 26 (19%) participants for depression. The HCV group had a significantly higher prevalence of depression than either of the other groups (HCV = 34%, IBS = 15% and IBD = 11%, p = 0.009). In the SCL90, the three disease groups differed on 7 out of 12 subscales. On each of these subscales, the HCV group were most severely affected and differed most from the general population.Conclusion
Patients with these common chronic gastrointestinal diseases have significant impairment of quality of life. Anxiety is a greater problem than depression, although patients with HCV in particular, should be regularly monitored and treated for co-morbid depression. Evaluation of specific psychological interventions targeting anxiety is warranted.100.
O'Mahony S; Morris AJ; Straiton M; Murray L; MacKenzie JF 《QJM : monthly journal of the Association of Physicians》1996,89(9):685-690
We report our experience with small-bowel push enteroscopy in 50 patients.
The indications for push enteroscopy were: anaemia/occult gastrointestinal
bleeding (22 patients); overt gastrointestinal bleeding (17 patients);
abnormal small-bowel radiology (8 patients) and miscellaneous (3 patients).
In those with undiagnosed gastrointestinal bleeding/anaemia, abnormalities
were detected in 24/39 patients (62%): small bowel arteriovenous
malformations (AVMs) were detected in 19 (49%), and five (13%) had lesions
in the upper gastrointestinal tract. Seventeen patients had heater-probe
ablation therapy of vascular lesions: nine patients had small-intestinal
lesions, four patients gastric lesions, and four patients combined gastric
and small- intestinal lesions. In those with abnormal small-bowel
radiology, abnormalities were detected in 6/8 patients. We conclude that
(i) push enteroscopy can establish a diagnosis in a high proportion of
patients with gastrointestinal bleeding; (ii) heater-probe ablation therapy
of vascular lesions can be performed routinely at the time of enteroscopy;
(iii) a significant proportion of patients (9/50) referred for enteroscopy
with undiagnosed gastrointestinal bleeding have lesions in the
stomach/proximal duodenum missed at diagnostic endoscopy. Push enteroscopy
is a valuable diagnostic and therapeutic endoscopic procedure.
相似文献