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   1891篇
  免费   122篇
  国内免费   6篇
耳鼻咽喉   25篇
儿科学   139篇
妇产科学   47篇
基础医学   175篇
口腔科学   55篇
临床医学   121篇
内科学   533篇
皮肤病学   53篇
神经病学   141篇
特种医学   48篇
外科学   279篇
综合类   33篇
一般理论   3篇
预防医学   54篇
眼科学   106篇
药学   107篇
肿瘤学   100篇
  2024年   2篇
  2023年   40篇
  2022年   51篇
  2021年   119篇
  2020年   64篇
  2019年   77篇
  2018年   100篇
  2017年   64篇
  2016年   57篇
  2015年   59篇
  2014年   79篇
  2013年   120篇
  2012年   178篇
  2011年   146篇
  2010年   105篇
  2009年   93篇
  2008年   107篇
  2007年   100篇
  2006年   69篇
  2005年   57篇
  2004年   59篇
  2003年   51篇
  2002年   48篇
  2001年   18篇
  2000年   13篇
  1999年   20篇
  1998年   4篇
  1997年   2篇
  1995年   6篇
  1994年   2篇
  1992年   6篇
  1991年   7篇
  1990年   8篇
  1989年   4篇
  1988年   8篇
  1987年   8篇
  1986年   4篇
  1985年   4篇
  1984年   4篇
  1983年   8篇
  1981年   2篇
  1978年   5篇
  1977年   3篇
  1976年   2篇
  1974年   10篇
  1973年   2篇
  1972年   6篇
  1971年   3篇
  1969年   4篇
  1968年   3篇
排序方式: 共有2019条查询结果,搜索用时 0 毫秒
991.
992.
993.
994.
The lymphoproliferative responses of 51 leprosy patients and 11 healthy contacts were analyzed using the nitrocellulose-bound specific antigen fractions from the cell-free extract of Mycobacterium leprae. The main proliferation-inducing fraction for peripheral blood mononuclear cells of the healthy contacts was found to be the Fraction II, bearing antigens in the range of 66-45 kDa. However, this fraction failed to induce lymphoproliferation in the leprosy patients, unlike healthy contacts (p < 0.032). The number of responders as well as the strength of the responses to 66-45 kDa proteins were found to be low in the leprosy patients compared to the healthy contacts. Further, preliminary analysis with the subfractions of Fraction II produced a similar pattern, suggesting that the immune response to the antigens in the range of 66-45 kDa M. leprae proteins remains suppressed in subjects with clinical signs and symptoms of the disease.  相似文献   
995.
Skeletal hydatidosis results from the deposition of the larval form of the Echinococcus, a genus of tapeworm. The incidence of bone disease is extremely low as most larvae are trapped by the liver and lung upon release of the embryo into the portal blood stream. The interpretation of imaging studies can prove very confusing because bone changes evolve with time, and the non‐specificity of these findings often leads to a mistaken diagnosis. We present the case of a 35‐year‐old woman with long‐standing pain in the left hip joint in which the findings on CT were thought of as being either tuberculous or neoplastic in nature. The result of a CT‐guided biopsy and another done following surgery concurred on an unexpected diagnosis of a hydatid cyst. This case illustrates that in the absence of a high index of suspicion for echinococcal infection, the semblance of imaging findings of hydatid disease in bone to those of other skeletal pathologies can lead to misinterpretation.  相似文献   
996.
997.
Three decades after the coining of the term chronic fatigue syndrome, the diagnosis of this illness is still symptom based and the aetiology remains elusive. Chronic fatigue syndrome pathogenesis seems to be multifactorial and the possible involvement of immune system is supported. The present study was designed to evaluate the effects of the epigallocatechin gallate in a mouse model of immunologically induced chronic fatigue. On 19th day, after lipopolysaccharide/Brucella abortus administration, the mice showed significant increase in immobility period, post swim fatigue and thermal hyperalgesia. Behavioral deficits were coupled with enhanced oxidative–nitrosative stress as evident by increased lipid peroxidation, nitrite levels and decreased endogenous antioxidant enzymes (superoxide dismutase, reduced glutathione and catalase) and inflammation (increased levels of tumor necrosis factor-α and tissue growth factor-β). Chronic treatment with epigallocatechin gallate restored these behavioral and biochemical alterations in mice. The present study points out towards the beneficial effect of epigallocatechin gallate in the amelioration of chronic fatigue syndrome and thus may provide a new, effective and powerful strategy to treat chronic fatigue syndrome.  相似文献   
998.
Dopamine is an endogenous natriuretic amine that contributes to the maintenance of sodium homeostasis. Deficiencies in the renal production of dopamine and the action of dopamine on renal tubular receptors have been observed in human hypertension and may contribute to salt sensitivity of blood pressure. Ethnic differences in the sodium‐to‐dopamine relationship may contribute to the higher prevalence of salt sensitivity in blacks. The authors assessed dopaminergic activity in two studies. In the first, daytime and nighttime excretion of sodium and dopamine were compared in 11 black and 17 white normotensive patients. No racial difference in the rate of sodium or dopamine excretion during either period was observed. In the second study, a graded infusion of the dopamine‐1 receptor agonist, fenoldopam, was performed in 14 black and 17 white normotensive patients. There was no racial difference in the natriuretic responses. Previously described lower rates of renal free water clearance and potassium excretion in blacks compared with whites were maintained during fenoldopam infusion, suggesting that dopamine is not a mediator of those differences. The authors conclude that there are no race‐related differences in dopamine excretion or activity in normotensive patients.  相似文献   
999.
Despite the widespread use of tobacco and marijuana by cocaine abusers, it remains unclear whether combined tobacco and marijuana smoking is more harmful than tobacco smoking alone in cocaine abusers. We investigated the differences in medical symptoms reported among 34 crack cocaine abusers who did not smoke tobacco or marijuana (C), 86 crack cocaine abusers who also smoked tobacco (C + T), and 48 crack abusers who smoked both tobacco and marijuana (C + T + M). Medical symptoms were recorded using a 134-item self-report instrument (MILCOM), and drug use was assessed using the Addiction Severity Index (ASI). After controlling for clinical and demographic differences, the C + T + M group reported significantly more total symptoms on the MILCOM as well as on the respiratory, digestive, general, and nose/throat subscales than the C + T or C groups. The C + T group reported higher total and respiratory and nose/throat symptoms than the C group. HOwever, the C group had the highest number of mood symptoms among the three groups. The C + T and C + T + M groups were comparable in number of cigarettes smoked and ASI scores. Although tobacco smoking is associated with higher reports of medical problems in crack abusers, smoking both marijuana and tobacco seems to be associated with greater medical problems than smoking tobacco alone. Tobacco smoking was not related to changes in cocaine use. Also, marijuana smoking does not appear to be associated with a reduction in tobacco or cocaine use.  相似文献   
1000.
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