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   2683篇
  免费   178篇
  国内免费   7篇
耳鼻咽喉   28篇
儿科学   219篇
妇产科学   45篇
基础医学   236篇
口腔科学   42篇
临床医学   193篇
内科学   600篇
皮肤病学   90篇
神经病学   91篇
特种医学   100篇
外国民族医学   1篇
外科学   377篇
综合类   338篇
一般理论   1篇
预防医学   182篇
眼科学   45篇
药学   149篇
  1篇
中国医学   5篇
肿瘤学   125篇
  2023年   16篇
  2022年   31篇
  2021年   70篇
  2020年   44篇
  2019年   52篇
  2018年   57篇
  2017年   48篇
  2016年   49篇
  2015年   73篇
  2014年   99篇
  2013年   137篇
  2012年   162篇
  2011年   141篇
  2010年   124篇
  2009年   115篇
  2008年   117篇
  2007年   136篇
  2006年   164篇
  2005年   135篇
  2004年   143篇
  2003年   113篇
  2002年   122篇
  2001年   80篇
  2000年   57篇
  1999年   53篇
  1998年   39篇
  1997年   41篇
  1996年   40篇
  1995年   31篇
  1994年   28篇
  1993年   18篇
  1992年   23篇
  1991年   18篇
  1990年   14篇
  1989年   20篇
  1988年   26篇
  1987年   17篇
  1986年   23篇
  1985年   20篇
  1984年   21篇
  1983年   13篇
  1982年   13篇
  1981年   10篇
  1980年   8篇
  1979年   9篇
  1978年   14篇
  1976年   14篇
  1975年   7篇
  1974年   7篇
  1973年   14篇
排序方式: 共有2868条查询结果,搜索用时 15 毫秒
61.
Venous thromboembolism (VTE) has long been considered a disease that affects predominantly white populations, a misconception resulting from a paucity of epidemiological data from non-Western countries, and the low incidence of hereditary thrombophilia in those of non-Caucasian background. Over the last decade, interest has grown in this area with the emergence of evidence that VTE is as prevalent, if not more so, in the black population and is also common in Asian groups. Much is still to be learned, as our current knowledge of hereditary thrombophilia and acquired risk factors do not fully explain the risk of VTE in non-Caucasian groups. This review summarises the current understanding of ethnic variation in VTE and highlights the need for further research in this area.  相似文献   
62.
63.
Lee  SB; Rao  AK; Lee  KH; Yang  X; Bae  YS; Rhee  SG 《Blood》1996,88(5):1684-1691
Platelets from a patient with a mild inherited bleeding disorder and abnormal platelet aggregation and secretion show reduced generation of inositol 1,4,5-trisphosphate, mobilization of intracellular Ca2+, and phosphorylation of pleckstrin in response to several G protein mediated agonists, suggesting a possible defect at the level of phospholipase C (PLC) activation (see accompanying report). A procedure was developed that allows quantitation of platelet PLC isozymes. After fractionation of platelet extracts by high-performance liquid chromatography, 7 out of 10 known PLC isoforms were detected by immunoblot analysis. The amount of these isoforms in normal platelets decreased in the order PLC- gamma 2 > PLC-beta 2 > PLC-beta 3 > PLC-beta 1 > PLC-gamma 1 > PLC- delta 1 > PLC-beta 4. Compared with normal platelets, platelets from the patient contained approximately one-third the amount of PLC-beta 2, whereas PLC-beta 4 was increased threefold. These results suggest that the impaired platelet function in the patient in response to multiple G protein mediated agonists is attributable to a deficiency of PLC-beta 2. They document for the first time a specific PLC isozyme deficiency in human platelets and provide an unique opportunity to understand the role of different PLC isozymes in normal platelet function.  相似文献   
64.
65.
Yang  X; Sun  L; Ghosh  S; Rao  AK 《Blood》1996,88(5):1676-1683
Signal transduction on platelet activation involves phosphoinositide- specific phospholipase C (PLC)-mediated hydrolysis of phosphatidylinositides and formation of inositol-1,4,5-triphosphate [I(1,4,5)P3], which mediates Ca2+ mobilization, and diacylglycerol (DG), which activates protein kinase C (PKC) to phosphorylate a 47-kD protein (Pleckstrin). We studied these events in two related patients previously reported (Blood 74:664, 1989) to have abnormal aggregation and 14C-serotonin secretion, and impaired intracellular Ca2+ mobilization in response to several agonists. Thrombin-induced I(1,4,5)P3 and phosphatidic acid formation were diminished. Pleckstrin phosphorylation was impaired on activation with thrombin, platelet- activating factor, and ionophore A23187, but was normal with PKC activator 1,2-dioctonyl-sn-glycerol (DiC8). Ca2+ mobilization induced by guanosine triphosphate (GTP) analog guanosine 5'-0-(3 thiotriphosphate) (GTP gamma S) was diminished. Pretreatment with either A23187 or DiC8 did not correct the impaired adenine diphosphate- induced secretion; however, upon stimulation with A23187 plus DiC8, pleckstrin phosphorylation and secretion were normal, indicating that both PKC activation and Ca2+ mobilization are essential for normal secretion. We conclude that these patients have a unique inherited platelet defect in formation of two key intracellular mediators [I(1,4,5)P3 and DG] and in the responses mediated by them due to a defect in postreceptor mechanisms of PLC activation.  相似文献   
66.
Obesity, one of the most prevalent health problems in the Western world, is a chronic and progressive condition. Therefore, as with other chronic diseases, patients with obesity require lifelong treatment. Long-term efficacy and effectiveness of obesity treatments is notoriously poor. This may in part be attributable to the substantial barriers that undermine long-term obesity management strategies. These can include lack of recognition of obesity as a chronic condition, low socioeconomic status, time constraints, intimate saboteurs, and a wide range of comorbidities including mental health, sleep, chronic pain, musculoskeletal, cardiovascular, respiratory, digestive and endocrine disorders. Furthermore, medications used to treat some of these disorders may further undermine weight-loss efforts. Lack of specific obesity training of health professionals, attitudes and beliefs as well as coverage and availability of obesity treatments can likewise pose important barriers. Health professionals need to take care to identify, acknowledge and address these barriers where possible to increase patient success as well as compliance and adherence with treatments. Failure to do so may further undermine the sense of failure, low self esteem and self efficacy already common among obese individuals. Addressing treatment barriers can save resources and increase the prospect of long-term success.  相似文献   
67.

Background:

Hyperphenylalaninemia (HPA) and Phenylkeonuria (PKU) are metabolic errors caused by deficiency of phenylalanine hydroxylase enzyme, which results in increased level of phenylalanine. This increase is toxic to the growing brain.

Objectives:

The purpose of this study was to compare the intellectual and developmental status in HPA and PKU children with normal population in national screening program.

Patients and Methods:

In a historical cohort study, 41 PKU patients who had the inclusion criteria and 41 healthy children were evaluated. Wechsler preschool and primary scale of intelligence-3rd edition (WPPI-3) was used in order to assess the intellectual status of children 4 years and older and Ages and stages questionnaire (ASQ) was used to assess the developmental status of children 5 years and younger.

Results:

In intellectual test comparison, the two groups showed significant difference in Wechsler’s performance intelligence score and some performance subscales (P-value < 0.01). In comparison of developmental status, no significant difference was observed between the two groups (P-value > 0.05).

Conclusions:

Even with early diagnosis and treatment of PKU patients, these children show some deficiencies intellectually compared to normal children. This study emphasizes on necessity for screening intellectual and developmental status of PKU patients so that effective medical or educational measures can taken in case of deficiencies.  相似文献   
68.
Immunoglobulin V regions and the B cell   总被引:7,自引:2,他引:7  
Stewart  AK; Schwartz  RS 《Blood》1994,83(7):1717-1730
  相似文献   
69.
Metabolic Brain Disease - Mild cognitive impairment (MCI) is transition phase between cognitive decline and dementia. The current study aims to investigate altered metabolic pattern in plasma of...  相似文献   
70.
Hepatitis E virus (HEV) is an important cause of repeated waterborne outbreaks of acute hepatitis. Recently, several extrahepatic manifestations (EHMs) have been described in patients with HEV infection. Of these, neurological disorders are the most common EHM associated with HEV. The involvement of both the peripheral nervous system and central nervous system can occur together or in isolation. Patients can present with normal liver function tests, which can often be misleading for physicians. There is a paucity of data on HEV-related neurological manifestations; and these data are mostly described as case reports and case series. In this review, we analyzed data of 163 reported cases of HEV-related neurological disorders. The mechanisms of pathogenesis, clinico-demographic profile, and outcomes of the HEV-related neurological disorders are described in this article. Nerve root and plexus disorder were found to be the most commonly reported disease, followed by meningoencephalitis.  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