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   940篇
  免费   50篇
  国内免费   19篇
耳鼻咽喉   3篇
儿科学   35篇
妇产科学   15篇
基础医学   111篇
口腔科学   11篇
临床医学   103篇
内科学   304篇
皮肤病学   15篇
神经病学   36篇
特种医学   48篇
外科学   88篇
综合类   24篇
预防医学   81篇
眼科学   11篇
药学   87篇
肿瘤学   37篇
  2016年   9篇
  2015年   19篇
  2014年   25篇
  2013年   29篇
  2012年   38篇
  2011年   36篇
  2010年   50篇
  2009年   32篇
  2008年   22篇
  2007年   29篇
  2006年   19篇
  2005年   20篇
  2004年   17篇
  2003年   18篇
  2002年   24篇
  2001年   13篇
  2000年   21篇
  1999年   16篇
  1998年   34篇
  1997年   22篇
  1996年   26篇
  1995年   14篇
  1994年   17篇
  1993年   18篇
  1992年   11篇
  1991年   22篇
  1990年   9篇
  1989年   20篇
  1988年   24篇
  1987年   12篇
  1986年   17篇
  1985年   12篇
  1983年   16篇
  1982年   12篇
  1981年   8篇
  1980年   10篇
  1979年   13篇
  1977年   8篇
  1975年   11篇
  1973年   8篇
  1972年   8篇
  1970年   8篇
  1966年   9篇
  1959年   15篇
  1958年   16篇
  1957年   14篇
  1956年   10篇
  1955年   15篇
  1954年   19篇
  1949年   10篇
排序方式: 共有1009条查询结果,搜索用时 31 毫秒
81.
白介素与溃疡性结肠炎   总被引:17,自引:1,他引:17  
近年来对白介素(interleukin,IL)和溃疡性结肠炎(ulcerative colitis,UC)的研究取得了很大进展,我们通过总结整理以前有关IL和UC的文献,概括出IL的产生和在UC发病及病理变化中的作用机制:IL-1直接介导了UC初期阶段炎症的发生:IL-8、IL-6直接促进炎性细胞过度分泌和/或抑制了炎性细胞的凋亡,IL-2分泌减少导致免疫系统内细胞间网络调节失衡, 使局部炎症介质和自由基释放,引起细胞毒作用,IL主要通过影响机体整体和/或局部免疫系统的功能介导UC的产生,并与UC的迁延难愈和反复发作有关.  相似文献   
82.

Introduction

Weight gain after gastric bypass can occur in up to 10% of patients 5 years following and in about 20% of patients 10 years following surgery. The nadir weight is usually reached within the first 2 years after bypass surgery. However, weight may slowly be regained for numerous reasons. This phenomenon has been studied extensively, but there is often no one reason this occurs. Once psychological and dietary reasons have been investigated, revisional surgery may be the only alternative for treatment. Revisional gastric bypass surgery is associated with a much higher morbidity and mortality when compared with a primary gastric bypass procedure.

Patients and methods

Thirty-nine patients underwent endoluminal gastric pouch reduction with the StomaphyXTM device after informed consent. The StomaphyXTM device is a sterile, single-use device for use in endoluminal transoral tissue approximation and ligation in the gastrointestinal (GI) tract.

Results

Average age was 47.8 (29–64) years, and 36/39 (92.3%) patients were female. Average body mass index (BMI) and weight prior to the StomaphyXTM procedure were 39.8 (22.7–63.2) kg/m2 and 108.0 kg (65.90–172.2 kg). The average preprocedure excess body weight was 51.1 kg. Weight loss at 2 weeks (n = 39) was 3.8 kg (7.4% excess body weight loss, EBWL), at 1 month (n = 34) was 5.4 kg (10.6% EBWL), at 2 months (n = 26) was 6.7 kg (13.1% EBWL), at 3 months (n = 15) was 6.7 kg (13.1% EBWL), at 6 months (n = 14) was 8.7 kg (17.0% EBWL), and at 1 year (n = 6) was 10.0 kg (19.5% EBWL). No major complications were observed. The minor complications that were seen included a sore throat lasting less than 48 h in 34/39 patients (87.1%) and epigastric pain that lasted for a few days in 30/39 patients (76.9%). Three patients with chronic diarrhea had their symptoms resolved after the procedure. Eight patients with gastroesophageal reflux disease reported improvement in their symptoms post procedure.

Conclusions

Endoluminal revision of gastric bypass patients with weight gain using the StomaphyXTM procedure may offer an alternative to open or laparoscopic revisional bariatric surgery.  相似文献   
83.
C Orkin  ST Sadiq  L Rice  F Jackson 《HIV medicine》2010,11(3):187-192

Objectives

Human leukocyte antigen (HLA)‐B*5701 is strongly associated with developing a hypersensitivity reaction to abacavir (ABC) in White and Hispanic subjects. Across the UK, limited data exist on HLA‐B*5701 prevalence in HIV‐1‐infected subjects. We determined HLA‐B*5701 prevalence in the general HIV‐1‐infected population and in specific ethnic groups, particularly Black Africans who, in general, exhibit greater genetic diversity. We also compared HLA‐B*5701 results obtained from local laboratories with those from a central provider.

Design and methods

Multi‐centre, observational study. All HIV‐1‐infected adult individuals receiving care at participating centres were eligible, irrespective of treatment status or prior exposure to ABC. Subjects provided samples for HLA‐B*5701 assessment by both local (blood) and central laboratories (buccal swabs). HLA‐B*5701 prevalence was adjusted to represent the ethnic group composition of the general UK population, and by main ethnic group.

Results

From eight UK centres, 1494 subjects [618 (41%) White, 770 (52%) Black] were recruited. Eighty‐nine per cent of Black subjects reported an immediate country of origin in Africa. Overall adjusted HLA‐B*5701 prevalence was 4.55% [95% confidence interval (CI) 3.49% to 5.60%]. Among White subjects, prevalence was 7.93% (CI 5.80% to 10.06%). Among Black subjects, only two (both Ugandan) were HLA‐B*5701 positive giving a rate of 0.26% (CI 0.07% to 0.94%).

Conclusions

HLA‐B*5701 prevalence was similar to previously reported rates in White HIV‐infected subjects but considerably lower than that reported in Black HIV‐1‐infected subjects, as a result of the large proportion of Black African subjects.  相似文献   
84.

Introduction

Discordance exists between the results of post-mortem studies and the low number of clinical reported cases of cardiac involvements in Wegener's granulomatosis.

Case reports

Data from four patients were studied retrospectively. Three patients had associated airway localization and three had kidney involvement. All patients had positive test for anti-PR3 antineutrophil antibodies. Two patients presented with dilated cardiomyopathy (one with terminal cardiac failure), another patient with complete atrioventricular block and pericarditis, and the remaining one with myopericarditis. One patient was asymptomatic. For three of these patients, the cardiac manifestations were contemporary of the diagnosis of Wegener's granulomatosis and had a severe disease course.

Conclusion

Cardiac events in Wegener's granulomatosis are probably underestimated, given the various type of heart damage and the clinical presentation. Cardiac involvement seems to be associated with a poor prognosis. Thus, we recommend systematic and regular cardiac assessment in the follow-up of patients with Wegener's granulomatosis.  相似文献   
85.
目前有些抗肿瘤药物尽管有较好的近期疗效,然而肿瘤患者单纯依赖化疗通常难以达到长期生存的目的。本文试图从肿瘤干细胞理论解释抗肿瘤药物近期疗效和远期生存之间存在的矛盾,并探讨抗肿瘤药物的研究发展方向。  相似文献   
86.
The effects of bromocriptine (10 mg/kg), known to inhibit prolactin secretion and lower autoimmune processes, were studied on glucose homeostasis in non-fasted non-obese diabetic mice, a spontaneous model of type 1 diabetes. Hyperglycemia was observed 120 and 240 min after i.p. but not s.c. injection. Bromocriptine administration i.p. led to rapid and marked hyperglycemia characterized by sexual dimorphism with males having higher glycemia than females. Bromocriptine induced a rapid but transient decrease in insulinemia in males only and biphasic increases in glucagon levels and a sustained stimulatory effect on circulating corticosterone in both sexes. Bromocriptine-induced hyperglycemia involved D2-dopaminergic receptors, as demonstrated by the inhibitory effect of the D2-dopamine antagonist, metoclopramide (10 mg/kg). Simultaneous injection of bromocriptine and metoclopramide also blocked the rise in blood corticosterone. In conclusion, by inducing hyperglycemia, i.p. bromocriptine administration to prediabetic autoimmune mice may counteract its beneficial anti-immunostimulatory effects.  相似文献   
87.

Objective

We assessed the influence of race/ethnicity and provider communication on overweight and obese patients’ perceptions of the damage weight causes to their health.

Methods

The study included 1071 overweight and obese patients who completed the 2002 Community Health Center (CHC) User survey. We used logistic regression analyses to examine determinants of patients’ perceptions of the impact of their weight on their health. Models were adjusted for covariates and weighting was used to account for the sampling design.

Results

Forty-one percent of respondents were overweight and 59% were obese. Non-Hispanic Blacks and Hispanics were half as likely as non-Hispanic Whites to believe weight was damaging to their health while controlling for covariates. Overweight/obese CHC patients who were told they were overweight by healthcare providers were almost nine times more likely to perceive that weight was damaging to their health compared to those not told.

Conclusions

We observed large racial/ethnic disparities in the perception that overweight is unhealthful but provider communication may be a powerful tool for helping patients understand that overweight is damaging to health.

Practice implications

Given obesity is a national epidemic, further attention to the role of patient provider communication in illness is essential with important implications for both health professional training and health care provision.  相似文献   
88.

Background  

Mandatory vaccination has contributed to the success of immunisation programmes but voluntary vaccination allows people to be responsible for their own health. There are benefits from both policies and the arguments between them remain subject to debate within and without the scientific community, both nationally and internationally. The aim of this study is to assess the opinions of those who actually work in the Vaccination Service.  相似文献   
89.
90.
Transparency is perceived when two or more objects or surfaces can be separated by the visual system whilst they are presented in the same region of the visual field at the same time. This segmentation of distinct entities on the basis of overlapping local visual cues poses an interesting challenge for the understanding of cortical information processing. In psychophysical experiments, we studied stimuli that contained randomly positioned disc elements, moving at two different speeds in the same direction, to analyse the interaction of cues during the perception of motion transparency. The current work extends findings from previous experiments with sine wave luminance gratings which only vary in one spatial dimension. The reported experiments manipulate low-level cues, like differences in speed or luminance, and what are likely to be higher level cues such as the relative size of the elements or the superposition rules that govern overlapping regions. The mechanism responsible for separation appears to be mediated by combination of the relevant and available cues. Where perceived transparency is stronger, the neural representations of components are inferred to be more distinguishable from each other across what appear to be multiple cue dimensions. The disproportionally large effect on transparency strength of the type of superposition of disc suggests that with this manipulation, there may be enhanced separation above what might be expected from the linear combination of low-level cues in a process we term labelling. A mechanism for transparency perception consistent with the current results would require a minimum of three stages; in addition to the local motion detection and global pooling and separation of motion signals, findings suggest a powerful additional role of higher level separation cues.  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