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   6407篇
  免费   318篇
  国内免费   63篇
耳鼻咽喉   69篇
儿科学   89篇
妇产科学   191篇
基础医学   494篇
口腔科学   194篇
临床医学   440篇
内科学   1600篇
皮肤病学   196篇
神经病学   588篇
特种医学   279篇
外科学   1104篇
综合类   40篇
预防医学   352篇
眼科学   192篇
药学   289篇
中国医学   9篇
肿瘤学   662篇
  2024年   3篇
  2023年   45篇
  2022年   105篇
  2021年   198篇
  2020年   129篇
  2019年   139篇
  2018年   192篇
  2017年   122篇
  2016年   182篇
  2015年   208篇
  2014年   314篇
  2013年   365篇
  2012年   510篇
  2011年   603篇
  2010年   327篇
  2009年   319篇
  2008年   499篇
  2007年   511篇
  2006年   424篇
  2005年   411篇
  2004年   339篇
  2003年   286篇
  2002年   241篇
  2001年   39篇
  2000年   28篇
  1999年   43篇
  1998年   42篇
  1997年   28篇
  1996年   23篇
  1995年   12篇
  1994年   13篇
  1993年   3篇
  1992年   11篇
  1991年   4篇
  1990年   2篇
  1989年   4篇
  1988年   8篇
  1987年   5篇
  1985年   2篇
  1984年   4篇
  1982年   5篇
  1981年   4篇
  1980年   9篇
  1979年   4篇
  1978年   3篇
  1977年   5篇
  1976年   3篇
  1975年   2篇
  1974年   3篇
  1963年   1篇
排序方式: 共有6788条查询结果,搜索用时 31 毫秒
41.
PROBLEM: The way by which intravenous immunoglobulin (IvIg) acts to prevent immunlogically mediated recurrent spontaneous abortions (RSA) has not been clarified. In the present study, a possible effect of IvIg on the T helper cell (Th1/Th2) balance was investigated in abortions of either alloimmune or autoimmune abnormalities. METHOD OF STUDY: The study included 21 women treated with IvIg before conception because of a history of RSA characterized by alloimmune abnormalities (n = 15) or associated with anti-phospholipid antibodies (APA) (n = 6). Peripheral blood samples, collected before and 5 days after the first IvIg infusion, were stimulated, and Th1 and Th2 cells were detected by flow-cytometric analysis using a combination of monoclonal antibodies against T-cell surface markers and intracellular interferon (IFN)-gamma and interleukin (IL)-4. The percentage of IFN-gamma-producing (Th1) and IL-4-producing (Th2) cells and the Th1/Th2 ratio were compared between pre- and post-infusion samples. RESULTS: A decrease of Th1 percentage in 66.6% of the cases and a concurrent Th2 percentage increase (47.61%) resulted in a decrease in the Th1/Th2 ratio in most of the cases (76.1%) (p < 0.01). Similar results were found in Group A (Th1/Th2 decreased in 60% of the cases, p < 0.05), while in Group B the effect of IvIg was not clear (Th1/Th2 increased in three and decreased in another three cases). CONCLUSION: Our finding suggests that IvIg administration in women with alloimmune RSA enhances Th2 polarization. This is not always the case with APA-associated abortions.  相似文献   
42.
43.
44.
Chronic allograft nephropathy is characterized by chronic inflammation and fibrosis. Because retinoids exhibit anti-proliferative, anti-inflammatory, and anti-fibrotic functions, the effects of low and high doses of 13-cis-retinoic acid (13cRA) were studied in a chronic Fisher344-->Lewis transplantation model. In 13cRA animals, independent of dose (2 or 20 mg/kg body weight/day) and start (0 or 14 days after transplantation) of 13cRA administration, serum creatinine was significantly lower and chronic rejection damage was dramatically reduced, including subendothelial fibrosis of preglomerular vessels and chronic tubulointerstitial damage. The number of infiltrating mononuclear cells and their proliferative activity were significantly diminished. The mRNA expression of chemokines (MCP-1/CCL2, MIP-1alpha/CCL3, IP-10/CXCL10, RANTES/CCL5) and proteins associated with fibrosis (plasminogen activator inhibitor-1, transforming growth factor-beta1, and collagens I and III) were strikingly lower in treated allografts. In vitro, activated peritoneal macrophages of 13cRA-treated rats showed a pronounced decrease in protein secretion of inflammatory cytokines (eg, tumor necrosis factor-alpha, interleukin-6). The suppression of the proinflammatory chemokine RANTES/CCL5 x 13cRA in fibroblasts could be mapped to a promoter module comprising IRF-1 and nuclear factor-kappaB binding elements, but direct binding of retinoid receptors to promoter elements could be excluded. In summary, 13cRA acted as a potent immunosuppressive and anti-fibrotic agent able to prevent and inhibit progression of chronic allograft nephropathy.  相似文献   
45.
Fast self-reported eating rate (SRER) has been associated with increased adiposity in children and adults. No studies have been conducted among high-school students, and SRER has not been validated vs. objective eating rate (OBER) in such populations. The objectives were to investigate (among high-school student populations) the association between OBER and BMI z-scores (BMIz), the validity of SRER vs. OBER, and potential differences in BMIz between SRER categories. Three studies were conducted. Study 1 included 116 Swedish students (mean ± SD age: 16.5 ± 0.8, 59% females) who were eating school lunch. Food intake and meal duration were objectively recorded, and OBER was calculated. Additionally, students provided SRER. Study 2 included students (n = 50, mean ± SD age: 16.7 ± 0.6, 58% females) from Study 1 who ate another objectively recorded school lunch. Study 3 included 1832 high-school students (mean ± SD age: 15.8 ± 0.9, 51% females) from Sweden (n = 748) and Greece (n = 1084) who provided SRER. In Study 1, students with BMIz ≥ 0 had faster OBER vs. students with BMIz < 0 (mean difference: +7.7 g/min or +27%, p = 0.012), while students with fast SRER had higher OBER vs. students with slow SRER (mean difference: +13.7 g/min or +56%, p = 0.001). However, there was “minimal” agreement between SRER and OBER categories (κ = 0.31, p < 0.001). In Study 2, OBER during lunch 1 had a “large” correlation with OBER during lunch 2 (r = 0.75, p < 0.001). In Study 3, fast SRER students had higher BMIz vs. slow SRER students (mean difference: 0.37, p < 0.001). Similar observations were found among both Swedish and Greek students. For the first time in high-school students, we confirm the association between fast eating and increased adiposity. Our validation analysis suggests that SRER could be used as a proxy for OBER in studies with large sample sizes on a group level. With smaller samples, OBER should be used instead. To assess eating rate on an individual level, OBER can be used while SRER should be avoided.  相似文献   
46.
Inguinal hernias are amongst the most common conditions requiring general surgical intervention. For decades, the preferred approach was the open repair. As laparoscopy became more popular and available and more surgeons became familiarized with this modality, laparoscopic inguinal hernia repair became an alternative. The aim of this study is to assess the effectiveness of laparoscopic inguinal repair, with a focus on bilateral inguinal hernias. Initial reports have shown promising clinical outcomes compared to those of conventional repair of bilateral hernias. However, there are only a few studies concerning laparoscopic repair of bilateral hernias. It is yet to be proven that laparoscopy is the “gold standard” in the treatment of bilateral inguinal hernias. So far, the choice of an inguinal hernia repair technique has been up to each surgeon, depending on their expertise and available resources after taking into consideration each patient’s needs.  相似文献   
47.
48.
During the last two decades, there have been several reports of an increasing incidence of type 2 diabetes mellitus (T2DM) in children and adolescents, especially among those belonging to minority ethnic groups. This trend, which parallels the increases in prevalence and degree of pediatric obesity, has caused great concern, even though T2DM remains a relatively rare disease in children. Youth T2DM differs not only from type 1 diabetes in children, from which it is sometimes difficult to differentiate, but also from T2DM in adults, since it appears to be an aggressive disease with rapidly progressive β-cell decline, high treatment failure rate, and accelerated development of complications. Despite the recent research, many aspects of youth T2DM still remain unknown, regarding both its pathophysiology and risk factor contribution, and its optimal management and prevention. Current management approaches include lifestyle changes, such as improved diet and increased physical activity, together with pharmacological interventions, including metformin, insulin, and the recently approved glucagon-like peptide-1 analog liraglutide. What is more important for everyone to realize though, from patients, families and physicians to schools, health services and policy-makers alike, is that T2DM is a largely preventable disease that will be addressed effectively only if its major contributor (i.e., pediatric obesity) is confronted and prevented at every possible stage of life, from conception until adulthood. Therefore, relevant comprehensive, coordinated, and innovative strategies are urgently needed.  相似文献   
49.
Despite the unequivocal value of vaccination in reducing the global burden of infectious diseases, the anti-vaccination movement thrives. The vast majority of the existing validated tools explore attitudes regarding vaccination in children. The aim of our study was to develop and validate a scale assessing attitudes towards adult immunisation. This national cross-sectional study included adult healthcare users who visited 23 Greek Primary Healthcare Units. The development of the scale was the result of literature review, semi-structured interviews and pilot testing of its preliminary versions. The initial version contained 15 items measuring respondents’ attitudes on a 6-point Likert scale. The sample was randomly split into two halves. Exploratory factor analysis, performed in the first sample, was used for the creation of multi-item scales; confirmatory factor analysis was used in the second sample to assess goodness of fit. Moreover, concurrent validity, internal consistency reliability, test–retest reliability and ceiling and floor effects were explored. The total sample consisted of 1,571 individuals. Overall ‘Cronbach's alpha’ (0.821) indicated good internal consistency. The initial exploratory factor analysis resulted in a three-factor model. The subsequent confirmatory factor analysis indicated that an 11-item version of the scale provided the best fit of the model to the data (RMSEA = 0.050, SRMR = 0.053, TLI = 0.937, CFI = 0.955, AIC = 24,999.949). All subscales (‘value of adult vaccination’, ‘safety concerns’ and ‘perceived barriers’) demonstrated strong concurrent associations with participants’ attitudes and behaviour regarding vaccination (p < .001). No ceiling or floor effects were noted for any of the subscales (0.13%, 2.61% and 0.51%; 0.13%, 0.57% and 0.45% respectively). The 11-item ATAVAC scale proved to be a reliable and valid tool, suitable for assessing attitudes towards adult vaccination.  相似文献   
50.
Vaginal hysterectomy: technique and results in the last twenty years   总被引:4,自引:0,他引:4  
The objective of this work was to describe patient characteristics and the effect of vaginal hysterectomy in a University hospital in the last two decades. A retrospective review of women undergoing vaginal hysterectomy was performed. The type of hysterectomy and complications were determined. From 1974 to 1994, a total of 6420 hysterectomies were performed. The vaginal route was used for 1530 patients. In the last decade, the Heaney method was used. A comparison of the periods 1974-1984 and 1984-1994 revealed that with the Heaney technique, we had significantly fewer complications, including less febrile morbidity, bleeding requiring transfusion, and injuries. Vaginal hysterectomy, specially using the Heaney method, is a rewarding challenge for any gynecologic surgeon. There are a low postoperative morbidity rate and a low mortality rate, which is well below the average mortality rate associated with abdominal hysterectomy.  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