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   1549篇
  免费   121篇
  国内免费   14篇
耳鼻咽喉   15篇
儿科学   85篇
妇产科学   21篇
基础医学   168篇
口腔科学   45篇
临床医学   133篇
内科学   268篇
皮肤病学   15篇
神经病学   120篇
特种医学   45篇
外科学   259篇
综合类   39篇
一般理论   2篇
预防医学   126篇
眼科学   108篇
药学   159篇
中国医学   13篇
肿瘤学   63篇
  2023年   22篇
  2022年   12篇
  2021年   74篇
  2020年   42篇
  2019年   42篇
  2018年   62篇
  2017年   44篇
  2016年   46篇
  2015年   48篇
  2014年   80篇
  2013年   83篇
  2012年   123篇
  2011年   123篇
  2010年   75篇
  2009年   56篇
  2008年   106篇
  2007年   66篇
  2006年   70篇
  2005年   65篇
  2004年   50篇
  2003年   54篇
  2002年   39篇
  2001年   24篇
  2000年   27篇
  1999年   21篇
  1998年   9篇
  1997年   8篇
  1996年   9篇
  1995年   8篇
  1994年   4篇
  1993年   5篇
  1992年   15篇
  1991年   15篇
  1990年   13篇
  1989年   12篇
  1988年   20篇
  1987年   13篇
  1986年   10篇
  1985年   10篇
  1984年   10篇
  1981年   5篇
  1980年   3篇
  1979年   7篇
  1978年   7篇
  1977年   3篇
  1975年   3篇
  1974年   7篇
  1973年   4篇
  1972年   5篇
  1965年   3篇
排序方式: 共有1684条查询结果,搜索用时 15 毫秒
1.
Novel coronavirus, SARS-CoV2, has caused pandemic of highly contagious disease called coronavirus disease 2019 (COVID-19), with epicenters in China, Italy,  相似文献   
2.
Brain tissues from 38 patients with a clinical suspicion of encephalitis or encephalopathy were examined by two immunoenzymatic techniques for the detection of arboviral antigen. Group B arboviral antigen was identified in 23 of these tissues. This simple method could be used for the diagnosis of the causal agent of encephalitis.  相似文献   
3.
Over the past 10 years, arteriography has become a well-established technique for the diagnosis of acute lower gastrointestinal bleeding, but not particularly for rectal bleeding. However, to the authors' knowledge, the technique of middle hemorrhoidal artery embolization has rarely been reported in the literature. In the present report, three patients with life-threatening rectal bleeding are presented, which was controlled by superselective embolization of the middle hemorrhoidal artery or selective embolization of the internal iliac artery as a last resort.  相似文献   
4.
Nonalcoholic steatohepatitis (NASH) associated cirrhosis is an increasing indication for liver transplant (LT). The aim of this study was to determine outcome and poor predictive factors after LT for NASH cirrhosis. We analyzed patients undergoing LT from 1997 to 2008 at a single center. NASH was diagnosed on histopathology. LT recipients with hepatitis C, alcoholic or cholestatic liver disease and cryptogenic cirrhosis acted as matched controls.
Ninety-eight LT recipients were identified with NASH cirrhosis. Compared to controls, NASH patients had a higher BMI (mean 32.3 kg/m2), and were more likely to be diabetic and hypertensive. Mortality after transplant was similar between NASH patients and controls but there was a tendency for higher earlier mortality in NASH patients (30-day mortality 6.1%, 1-year mortality 21.4%). Sepsis accounted for half of all deaths in NASH patients, significantly higher than controls. NASH patients ≥60 years, BMI ≥30 kg/m2 with diabetes and hypertension (HTN) had a 50% 1-year mortality.
In conclusion, patients undergoing LT for NASH cirrhosis have a similar outcome to patients undergoing LT for other indications. The combination of older age, higher BMI, diabetes and HTN are associated with poor outcome after LT. Careful consideration is warranted before offering LT to these high-risk patients.  相似文献   
5.
6.
We have examined the hypothesis that a variable number of tandem repeats in the third cytoplasmic loop of the dopamine D4 receptor influences clinical response to clozapine using a sample of 189 schizophrenic patients. Alleles of the 48-bp repeat, which range from two to ten copies in the normal human population, were analysed by the polymerase chain reaction using genomic DNA as template. Association between these alleles and response to clozapine was tested using the difference in pre-and post-treatment GAS scores as a measure of response. We found no statistically significant variation between genotypic groups and response by analysis of variance. We conclude that the variation of the number of 48-bp repeats alone does not determine response to clozapine. Larger studies are underway to determine if there is a more subtle relationship with sequence variation within the repeats or at other polymorphic sites within the gene that may provide evidence for a component of clozapine's action being at D4 receptors. © 1995 Wiley-Liss, Inc.  相似文献   
7.
The phenotype in the rd mouse is similar to the clinical presentation of Leber congenital amaurosis (LCA) in humans. Recently a nonsense mutation in the beta subunit of the cGMP phosphodiesterase (Pdeb) gene has been defined as the cause for the rd phenotype in the mouse and has raised the question as to whether mutations in the human PDEB gene might cause LCA. We have previously cloned and characterized the human homologue of the mouse Pdeb gene and have mapped it to chromosome 4p16.3. In this study, a total of 23 LCA families of various ethnic backgrounds have been investigated. Linkage analysis using highly polymorphic (CA)n microsatellites has excluded the PDEB gene as a cause for LCA in 6 families. In the remaining 17 families, we have searched for mutations in the 22 exons of the PDEB gene using single-strand gel electrophoresis (SSGE). Multiple exonic polymorphisms have been determined. However, no DNA changes in the PDEB gene have been identified in our study population which could be causative for the LCA phenotype.  相似文献   
8.
The effects of central infusion of naloxone into the midbrain periaqueductal gray (PAG) upon predatory attack behavior in the cat were studied in 12 cats. Initially, quiet biting attack was elicited by electrical stimulation of sites within the lateral hypothalamus using monopolar electrodes. Then cannula-electrodes were implanted into sites within the PAG from which electrical stimulation facilitated or suppressed the attack response. Following identification of modulatory sites within the PAG, naloxone (1.0 micrograms/0.5 microliter) was microinjected into those sites and the effects upon hypothalamically elicited attack were assessed. At nine of twelve sites in the PAG where suppression was obtained, administration of naloxone served to block those effects. Similarly, at six of eight facilitatory sites within the PAG, naloxone also blocked the modulatory effects of PAG stimulation. However, vehicle (isotonic saline) alone did not alter the modulatory effects of PAG stimulation. Administration of DAME (250 ng/0.3 microliter) into PAG modulatory sites in four cats, two which facilitated and two that suppressed the attack response, reversed the effects of naloxone at these sites. These results demonstrate that opioid peptides within the PAG play a complex role in the expression of predatory attack behavior in the cat.  相似文献   
9.
W. A. Shaikh 《Allergy》1992,47(4):327-330
Inhaled beclomethasone dipropionate (BDP) has been used with few side effects in the treatment of bronchial asthma for 2 decades. Until now the manifestation of tuberculosis (TB) in patients on inhaled BDP has not been reported. Eight patients with allergic asthma, of a total of 548 asthmatics (1.46%) seen over a 2-year period, developed active TB following the use of inhaled BDP. All were sputum-positive for acid-fast bacilli (AFB) on smear and/or culture, all responded well to a combination of anti-TB drugs, and none showed evidence of immunological or pituitary-adrenal suppression. Two patients agreed to a repeat administration of BDP; both developed TB again within 2 weeks and are again on anti-TB treatment.  相似文献   
10.
目的探讨西藏拉萨地区幽门螺杆菌(Helicobacter pyloric,Hp)感染与冠心病及多种危险因素的关系。为该地区冠心病的防治提供依据。方法分为冠心病组46例和非冠心病组51例,应用检测血抗HpIgG及-C-尿素呼气试验方法检测Hp感染情况,并分别测定各组血脂、血糖、餐后2h血糖、C反应蛋白、纤维蛋白原、白细胞总数。结果冠心病组患者血清抗HpIgG阳性率为50.0%(23/46),明显高于非冠心病组的23.5%(12/51),P〈0.05;冠心病患者Hp现症感染率为54.3%(25/46),明显高于非冠心病组的31.3%(27/51),P〈0.05;冠心病组Hp感染患者血脂、空腹及餐后2h血糖、C反应蛋白、纤维蛋白原较非感染患者明显升高(P〈0.05)。结论Hp感染与冠心病相关,可能是拉萨地区冠心病发病的独立危险因素。  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