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   3397篇
  免费   262篇
  国内免费   15篇
耳鼻咽喉   41篇
儿科学   106篇
妇产科学   85篇
基础医学   449篇
口腔科学   104篇
临床医学   414篇
内科学   765篇
皮肤病学   108篇
神经病学   279篇
特种医学   69篇
外科学   330篇
综合类   12篇
预防医学   421篇
眼科学   67篇
药学   222篇
中国医学   7篇
肿瘤学   195篇
  2024年   3篇
  2023年   32篇
  2022年   55篇
  2021年   120篇
  2020年   80篇
  2019年   111篇
  2018年   140篇
  2017年   81篇
  2016年   117篇
  2015年   129篇
  2014年   159篇
  2013年   205篇
  2012年   300篇
  2011年   298篇
  2010年   155篇
  2009年   142篇
  2008年   223篇
  2007年   228篇
  2006年   202篇
  2005年   191篇
  2004年   195篇
  2003年   154篇
  2002年   130篇
  2001年   21篇
  2000年   12篇
  1999年   15篇
  1998年   19篇
  1997年   14篇
  1996年   13篇
  1995年   12篇
  1994年   10篇
  1993年   12篇
  1992年   9篇
  1991年   6篇
  1990年   8篇
  1989年   4篇
  1988年   10篇
  1987年   9篇
  1986年   5篇
  1985年   4篇
  1984年   10篇
  1983年   3篇
  1982年   2篇
  1981年   4篇
  1980年   5篇
  1978年   3篇
  1974年   2篇
  1973年   2篇
  1972年   3篇
  1966年   1篇
排序方式: 共有3674条查询结果,搜索用时 15 毫秒
1.
2.
3.
Granulomatous slack skin is an indolent T-cell lymphoma, considered to be a variant of mycosis fungoides. Clinically it is characterized by areas of redundant skin, wrinkled, inelastic, with variable erythema and infiltration besides a poikilodermic surface. A differential diagnosis unknown to most dermatologists is the giant cell tumor of soft tissue, which is an extremely rare low-grade sarcoma. The authors report a patient who had undergone extensive surgery because of a primary diagnosis of giant cell tumor of soft tissue, but which proved to be granulomatous slack skin after a second interventional procedure with confirmatory histopathology.  相似文献   
4.
Harinakshi Sanikini  David C. Muller  Marisa Sophiea  Sabina Rinaldi  Antonio Agudo  Eric J. Duell  Elisabete Weiderpass  Kim Overvad  Anne Tjønneland  Jytte Halkjær  Marie-Christine Boutron-Ruault  Franck Carbonnel  Iris Cervenka  Heiner Boeing  Rudolf Kaaks  Tilman Kühn  Antonia Trichopoulou  Georgia Martimianaki  Anna Karakatsani  Valeria Pala  Domenico Palli  Amalia Mattiello  Rosario Tumino  Carlotta Sacerdote  Guri Skeie  Charlotta Rylander  María-Dolores Chirlaque López  Maria-Jose Sánchez  Eva Ardanaz  Sara Regnér  Tanja Stocks  Bas Bueno-de-Mesquita  Roel C.H. Vermeulen  Dagfinn Aune  Tammy Y.N. Tong  Nathalie Kliemann  Neil Murphy  Marc Chadeau-Hyam  Marc J. Gunter  Amanda J. Cross 《International journal of cancer. Journal international du cancer》2020,146(4):929-942
Obesity has been associated with upper gastrointestinal cancers; however, there are limited prospective data on associations by subtype/subsite. Obesity can impact hormonal factors, which have been hypothesized to play a role in these cancers. We investigated anthropometric and reproductive factors in relation to esophageal and gastric cancer by subtype and subsite for 476,160 participants from the European Prospective Investigation into Cancer and Nutrition cohort. Multivariable hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox models. During a mean follow-up of 14 years, 220 esophageal adenocarcinomas (EA), 195 esophageal squamous cell carcinomas, 243 gastric cardia (GC) and 373 gastric noncardia (GNC) cancers were diagnosed. Body mass index (BMI) was associated with EA in men (BMI ≥30 vs. 18.5–25 kg/m2: HR = 1.94, 95% CI: 1.25–3.03) and women (HR = 2.66, 95% CI: 1.15–6.19); however, adjustment for waist-to-hip ratio (WHR) attenuated these associations. After mutual adjustment for BMI and HC, respectively, WHR and waist circumference (WC) were associated with EA in men (HR = 3.47, 95% CI: 1.99–6.06 for WHR >0.96 vs. <0.91; HR = 2.67, 95% CI: 1.52–4.72 for WC >98 vs. <90 cm) and women (HR = 4.40, 95% CI: 1.35–14.33 for WHR >0.82 vs. <0.76; HR = 5.67, 95% CI: 1.76–18.26 for WC >84 vs. <74 cm). WHR was also positively associated with GC in women, and WC was positively associated with GC in men. Inverse associations were observed between parity and EA (HR = 0.38, 95% CI: 0.14–0.99; >2 vs. 0) and age at first pregnancy and GNC (HR = 0.54, 95% CI: 0.32–0.91; >26 vs. <22 years); whereas bilateral ovariectomy was positively associated with GNC (HR = 1.87, 95% CI: 1.04–3.36). These findings support a role for hormonal pathways in upper gastrointestinal cancers.  相似文献   
5.
6.
Central dopamine function is reduced by decreasing the availability of the catecholamine precursor, tyrosine, using a tyrosine-free amino acid mixture containing multiple large neutral as well as branched chain amino-acids, which compete with tyrosine for uptake into the brain. Current mixtures are cumbersome to make and administer, and unpalatable to patients and volunteers. Here, we investigate whether individual or limited amino-acid combinations could reduce brain tyrosine levels and hence dopamine function. Measurements of regional brain tyrosine levels, catecholamine and indoleamine synthesis (L-DOPA and 5-HTP accumulation, respectively) were used to identify an effective paradigm to test in neurochemical, behavioral and fos immunocytochemical models. Administration of leucine or isoleucine, or a mixture of leucine, isoleucine, and valine reduced tyrosine and 5-HTP, but not L-DOPA accumulation. A mixture of leucine, valine, and isoleucine supplemented with tryptophan reduced brain tyrosine and L-DOPA, but not 5-HTP. In microdialysis experiments this amino-acid mixture reduced basal and amphetamine-evoked striatal dopamine release, as well as amphetamine-induced hyperactivity. This mixture also reduced amphetamine-induced fos expression in striatal areas. In conclusion, the present study identified a small combination of amino acids that reduces brain tyrosine and dopamine function in a manner similar to mixtures of multiple amino acids. This minimal mixture may have use as a dopamine reducing paradigm in patient and volunteer studies.  相似文献   
7.
This case report describes infantile nephrotic syndrome (NS) in a baby girl with a clinically severe cytomegalovirus (CMV) infection. Culture of the baby's urine was positive for CMV and IgM anti-CMV antibodies were detected. After an unsuccessful course of corticosteroids, gancyclovir treatment was started and a remission of cutaneous, pulmonary, and renal symptoms was achieved. As the mother also developed NS at the end of pregnancy, a common etiology could be postulated, although there were no signs of recent CMV infection in the mother, only anti-CMV IgG. The relationship between CMV infection and glomerular disease is still unclear: NS may represent another manifestation of CMV disease.  相似文献   
8.
The objective of this study was to explore whether the items from a specific outcome measure, that is, Disabilities of the Arm, Shoulder, and Hand (DASH), for quantifying limb symptoms and functions in musculoskeletal disorders fit into the framework of the International Classification of Functioning, Disability and Health (ICF). All DASH items were compared to the ICF according to eight linking rules. Two groups of researchers performed the linking independently, and the results were compared by correlation. The 30 DASH items and four items from the optional modules were linked to 63 ICF categories and 11 chapters: 15 categories belong to the ICF body functions component and 48 to the activities and participation component. There were no items coded under the components body structure or environmental factors. Kappa index showed an agreement of 0.73 (p<0.001). The results showed that the content of the DASH does link well with the ICF framework. Clinicians and researchers must attend to the fact that certain domains and categories from the ICF are not covered by the DASH. Limitations of the instrument may be overcome by simultaneously using other instruments that address the intended content.  相似文献   
9.
Systemic lupus erythematosus (SLE) is the archetypical immunologic disease. Approximately 20% of patients present in the first two decades of life. This article highlights some of the differences between pediatric and adult onset lupus.Children are defined as different from adults on the basis of age. Lupus presents with different gender ratios based on hormonal or pubertal status with more significant skewing toward female patients in the childbearing years. Female patients in the childbearing years appear to have a higher relative risk for mortality. Despite this, children have greater disease severity at onset based on the number of patients who present with significant organ inflammation, the amount of corticosteroids required and the abnormalities in lupus serologies including autoantibodies and low complements. Children present frequently with congenital and acquired complement defects. Children have an increased risk of infections that can be confused with lupus. They have a higher risk of serious pneumococcal infection and may have less protection from vaccinations received at the time of disease onset.The clinical immunology laboratory is critical in the diagnosis and treatment of pediatric SLE. The rapid analysis and transfer of laboratory results can be life saving for the child with suspected new onset lupus. The laboratory is also helpful in determining disease activity through analysis of immunologic trends over time in pediatric lupus patients. This is especially important in the noncompliant adolescent patient who has a correlation between disease activity and lupus serologic tests. Finally, the clinical immunology laboratory is an important tool for better understanding of the immunologic phenomena associated with lupus and of disease pathophysiology.  相似文献   
10.
OBJECTIVE: To determine the natural history of colonization with vancomycin-resistant enterococci (VRE), methicillin-resistant Staphylococcus aureus (MRSA), and resistant gram-negative bacilli among long-term-care facility (LTCF) residents. DESIGN: Observational cohort study. SETTING: A 355-bed LTCF with a ventilator unit and a subacute unit. PARTICIPANTS: Residents with colonization or infection with VRE, MRSA, or resistant gram-negative bacilli housed at the LTCF between December 1, 1999, and February 29, 2000. METHODS: Cultures of clinical and surveillance sites were performed at regular intervals. Charts were reviewed for clinical characteristics associated with clearance of colonization. Kaplan-Meier curves were constructed to analyze the number of days to clearance of colonization. RESULTS: Forty-nine residents had 65 episodes of colonization (27 VRE, 30 MRSA, and 8 resistant gram-negative bacilli). Eighteen (28%) of the episodes cleared. The clearance rate was 2.7 episodes per 1,000 person-days. Clearance occurred significantly more often with resistant gram-negative bacilli colonization compared with VRE or MRSA colonization (6 [75%] vs 12 [21%]; P = .007; relative risk, 4.17; 95% confidence interval, 1.26 to 11.8). There was a trend toward longer use of antimicrobial agents among residents with persistent colonization. Infections occurred most frequently with MRSA. The urinary tract was the most common site of infection. CONCLUSION: Among LTCF residents, colonization with resistant gram-negative bacilli is four times more likely to clear than colonization with VRE or MRSA. Performance of surveillance cultures at regular intervals may reduce the need for contact precautions for LTCF residents with resistant gram-negative bacilli colonization.  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