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   16242篇
  免费   1124篇
  国内免费   133篇
耳鼻咽喉   142篇
儿科学   472篇
妇产科学   466篇
基础医学   2498篇
口腔科学   284篇
临床医学   1336篇
内科学   3811篇
皮肤病学   384篇
神经病学   2254篇
特种医学   444篇
外科学   1512篇
综合类   32篇
一般理论   1篇
预防医学   914篇
眼科学   185篇
药学   1162篇
中国医学   32篇
肿瘤学   1570篇
  2024年   19篇
  2023年   195篇
  2022年   358篇
  2021年   745篇
  2020年   404篇
  2019年   500篇
  2018年   654篇
  2017年   477篇
  2016年   550篇
  2015年   609篇
  2014年   756篇
  2013年   994篇
  2012年   1407篇
  2011年   1413篇
  2010年   786篇
  2009年   717篇
  2008年   1191篇
  2007年   1076篇
  2006年   981篇
  2005年   871篇
  2004年   801篇
  2003年   703篇
  2002年   540篇
  2001年   66篇
  2000年   54篇
  1999年   62篇
  1998年   109篇
  1997年   67篇
  1996年   49篇
  1995年   42篇
  1994年   49篇
  1993年   24篇
  1992年   32篇
  1991年   27篇
  1990年   27篇
  1989年   18篇
  1988年   18篇
  1987年   13篇
  1986年   18篇
  1985年   15篇
  1984年   9篇
  1983年   6篇
  1982年   6篇
  1981年   6篇
  1980年   9篇
  1979年   7篇
  1978年   2篇
  1975年   4篇
  1974年   4篇
  1969年   3篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Coronary arterial inflammation in acute Kawasaki disease (KD) is characterized by transmural infiltration of CD8 T lymphocytes, suggesting that CD8 T lymphocyte cytotoxic activity may be important in the pathogenesis of coronary arterial damage in acute KD. We performed immunohistochemistry for the cytotoxic proteins perforin and granzyme B on paraffin-embedded, formalin-fixed coronary artery aneurysm tissue from 6 children who died in the acute stage of KD. Neither perforin nor granzyme B was detected in the KD coronary aneurysm wall. We speculate that the etiologic agent of KD interferes with expression of these cytotoxic proteins by CD8 T lymphocytes, prolonging inflammation in the arterial wall and leading to coronary artery aneurysm formation.  相似文献   
993.
Chronic granulomatous disease (CGD) is a rare genetically determined immunodeficiency. Neutrophils from CGD patients show a defective killing of phagocytosed fungi and bacteria, due not only to an impairment in oxidative burst, but also to absence of normal pH value within phagocytic vacuole following phagocytosis. Because a weak base such as amantadine could potentially reverse these pH abnormalities, the authors used this drug to treat 2 CGD patients. They observed modifications of both phagosomal pH and killing activity on their neutrophils compared to those of healthy controls. Since the drug has been employed, the patients have not developed new infections, suggesting a role of amantadine as a part of CGD prophylactic regimen. These results suggest the opportunity of testing the drug in larger studies.  相似文献   
994.
OBJECTIVE: Sexually transmitted infections (STI) among adolescents continue to be an important public health problem for many industrialized and developing countries. This study evaluated knowledge and behaviour in adolescents regarding prevention of STI. METHODS: Information was obtained by using self-reported questionnaire from a random sample of 644 undergraduate students at university and at public high schools aged 14-20 years in Catanzaro (Italy). RESULTS: Only 14.2% of respondents knew about the main STI and that they can be transmitted through sexual intercourse with HIV seropositive partners; this knowledge was significantly higher among adolescents who had had a higher number of sexual partners in their lifetime and who had received information from physicians about STI. A total of 33.8% reported having had sexual intercourse at least once and the mean age at first intercourse was 16 years. Older males and adolescents with employed mothers were more likely to have reported having had a sexual experience. The prevalence of using condoms every time during sexual intercourse was 51.8% and such behaviour was more likely in younger adolescents and males. The prevalence of condom use on the last occasion of sex was 71.9%. Younger adolescents, those with a higher perception of the risk of contracting STI and those with lesser knowledge about STI were independent predictors for using condoms. The mean total score of the respondents' perception of a risk of contracting STI was 5.8. CONCLUSIONS: Evidence to develop and implement strategies with the hope of improving adolescents' level of knowledge and reducing unsafe sexual practices.  相似文献   
995.
OBJECTIVE: Fibromyalgia (FM) is a syndrome characterized by widespread musculoskeletal pain. Symptoms of orthostatic intolerance may also be present, suggesting underlying abnormalities of cardiovascular neural regulation. We tested the hypothesis that FM is characterized by sympathetic overactivity and alterations in cardiovascular autonomic response to gravitational stimulus. METHODS: Sixteen patients with primary FM and 16 healthy controls underwent electrocardiography examination, finger blood pressure, respiration, and muscle sympathetic nerve activity (MSNA) recordings at rest and during stepwise tilt test, up to 75 degrees . The autonomic profile was assessed by MSNA, plasma catecholamine, and spectral indices of cardiac sympathetic (LFRR in normalized units, NU) and vagal (HFRR both in absolute and NU) modulation and of sympathetic vasomotor control (LFSAP) computed by spectrum analysis of RR and systolic arterial pressure (SAP) variability. Arterial baroreflex function was evaluated by the SAP/RR spontaneous-sequences technique, the index a, and the gain of MSNA/diastolic pressure relationship during stepwise tilt test. RESULTS: At rest, patients showed higher values of heart rate, MSNA, LFRR NU, LF/HF, LFSAP, and reduced HFRR than controls. During tilt test, lack of increase of MSNA, less decrease of HFRR, and excessive rate (44%) of syncope were found in patients, suggesting reduced capability to enhance the sympathetic activity to vessels and withdraw the vagal modulation to sino-atrial node. Baroreflex function was similar in both groups. CONCLUSION: Patients with FM have an overall enhancement of cardiovascular sympathetic activity while recumbent. Lack of increased sympathetic discharge to vessels and decreased cardiac vagal activity characterize their autonomic profile during tilt test, and might account for the excessive rate of syncope.  相似文献   
996.
The direct expression and production of the critical osteoclastogenic factor, the receptor activator of NF-kB ligand (RANKL), is a matter of controversy. In this study we definitively demonstrate by both qualitative and quantitative polymerase chain reaction analysis that human myeloma cells do not express significant levels of RANKL mRNA or produce RANKL able to stimulate osteoclast formation.  相似文献   
997.
We report the successful use of bortezomib to treat a patient with multiple myeloma (MM) who had extramedullary relapse (paraspinal and thoracic masses and multiple cranial nerve palsy) after autologous and non-myeloablative allogeneic hematopoietic stem cell transplantation (HSCT).  相似文献   
998.
Congenitally corrected transposition of the great arteries (ccTGA) is a rare anomaly characterized by atrioventricular and ventriculo-arterial discordance and several other malformations that eventually lead to heart failure. We describe the case of a 53-year-old woman with ccTGA and aortic insufficiency who was a candidate for heart transplantation due to end-stage congestive heart failure. Her condition deteriorated before a suitable donor heart could be found; therefore, we placed a left ventricular assist device in the right (systemic) ventricle. Concomitantly, we removed the aortic (systemic) valve, closed the aortic annulus with a bovine pericardial patch, and repaired the mitral valve. The patient recovered uneventfully and was discharged from the hospital 2 months postoperatively. She underwent cardiac transplantation approximately 6 months later and continued to do well after 18 months.  相似文献   
999.
We find that CD11c(+) cells with many markers of dendritic cells (DCs) are a major cell type in the skin lesions of psoriasis. These CD11c(+) cells, which are evident in both epidermis and dermis, are the sites for the expression of two mediators of inflammation, inducible nitric oxide synthase (iNOS) and TNF-alpha in diseased skin. These cells express HLA-DR, CD40, and CD86, lack the Langerin and CD14 markers of Langerhans cells and monocytes, respectively, and to a significant extent express the DC maturation markers DC-LAMP and CD83. Treatment of psoriasis with efalizumab (anti-CD11a, Raptiva) strongly reduces infiltration by these DCs in patients responding to this agent. Disease activity after therapy was more related to DC infiltrates and iNOS mRNA levels than T cell infiltrates, and CD11c(+) cells responded more quickly to therapy than epidermal keratinocytes. Our results suggest that a type of DC, which resembles murine "Tip-DCs" that can accumulate during infection, has proinflammatory effects in psoriasis through nitric oxide and TNF-alpha production, and can be an important target for suppressive therapies.  相似文献   
1000.
Educators rarely consider the attitudes that determine whether a learner will use the clinical skills we teach. Nevertheless, many learners and practitioners exhibit negative attitudes that can impede the use of patient-centered skills, leading to an isolated focus upon disease and impairing the provider-patient relationship. The problem is compounded because these attitudes often are incompletely recognized by learners and therefore are difficult to change without help. We present a research-based method for teaching personal awareness of unrecognized and often harmful attitudes. We propose that primary care clinicians without mental health training can follow this method to teach students, residents, faculty, and practitioners. Such teachers/mentors need to possess an abiding interest in the personal dimension, patience with a slowly evolving process of awareness, and the ability to establish strong, ongoing relationships with learners. Personal awareness teaching may occur during instruction in basic interviewing skills but works best if systematically incorporated throughout training.  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