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   610篇
  免费   37篇
耳鼻咽喉   10篇
儿科学   22篇
妇产科学   3篇
基础医学   61篇
口腔科学   3篇
临床医学   66篇
内科学   167篇
皮肤病学   9篇
神经病学   46篇
特种医学   49篇
外科学   31篇
综合类   5篇
预防医学   70篇
眼科学   19篇
药学   31篇
中国医学   2篇
肿瘤学   53篇
  2023年   4篇
  2022年   5篇
  2021年   9篇
  2020年   10篇
  2019年   14篇
  2018年   12篇
  2017年   4篇
  2016年   15篇
  2015年   17篇
  2014年   19篇
  2013年   18篇
  2012年   41篇
  2011年   40篇
  2010年   21篇
  2009年   28篇
  2008年   50篇
  2007年   58篇
  2006年   55篇
  2005年   36篇
  2004年   21篇
  2003年   23篇
  2002年   11篇
  2001年   14篇
  2000年   8篇
  1999年   7篇
  1996年   3篇
  1995年   4篇
  1994年   4篇
  1992年   4篇
  1991年   4篇
  1990年   3篇
  1989年   5篇
  1988年   3篇
  1987年   4篇
  1986年   4篇
  1984年   4篇
  1983年   4篇
  1982年   7篇
  1981年   4篇
  1980年   6篇
  1979年   4篇
  1978年   3篇
  1977年   5篇
  1975年   3篇
  1973年   4篇
  1972年   3篇
  1971年   4篇
  1970年   2篇
  1969年   2篇
  1968年   2篇
排序方式: 共有647条查询结果,搜索用时 15 毫秒
41.
The Tolosa-Hunt syndrome   总被引:1,自引:0,他引:1  
The signs and symptoms of the Tolosa-Hunt syndrome are described and the results of orbital phlebography discussed. Emphasis is placed on the importance of systemic administration of corticosteroids, both as a diagnostic test and as a therapeutic measure.A case history is presented.  相似文献   
42.
43.
In northern Togo and Ghana, human infection with the parasitic nematode Oesophagostomum bifurcum is of major health importance. Elsewhere, oesophagostomiasis is considered a zoonotic infection, non-human primates being the natural host. We examined 349 faecal samples of the olive baboon, mona monkey and black and white colobus monkey from two geographically distinct areas in Ghana, outside the region endemic for O. bifurcum in humans. Using both microscopy and species-specific PCR, we found a high prevalence of O. bifurcum (75-99%) in olive baboons and mona monkeys. The majority of the test-positive faecal samples contained large numbers of larvae after copro-culture (>100). No O. bifurcum was detected in the faeces of the black and white colobus monkeys. Observational studies on the behaviour of the non-human primates, focusing on defecation, food consumption and the sharing of habitat with the local human population, indicated favourable conditions for zoonotic transmission. Given that no human infection with O. bifurcum has been reported from either study area, the present findings support the hypothesis that O. bifurcum from humans in the north of Ghana, and O. bifurcum from olive baboons and/or mona monkeys are distinct.  相似文献   
44.
OBJECTIVE: To investigate the risk factors for osteoporosis among a sample of middle-aged women. METHODS: Adipose tissue and bone mineral density levels at the left femur, lumbar spine, and total body were assessed using dual-energy x-ray absorptiometry (DXA). Subjects (n=342) were surveyed regarding a variety of osteoporosis-related risk factors. Forward stepwise multiple regression procedures were utilized. RESULTS: Menstrual status, hormone replacement therapy, adipose tissue, and dairy product intake were retained in the regression models. CONCLUSIONS: Osteoporosis prevention programs need to emphasize the importance of hormonal status and body composition in addition to obtaining adequate calcium intake.  相似文献   
45.
The possible role of acetylcholine as a modulator of neuronal differentiation has been tested using a neuroblastoma cell line (N18TG2), which does not synthesize any neurotransmitter. Acetylcholine synthesis has been activated in this line by transfection with a construct containing a choline acetyltransferase (ChAT) cDNA; ChAT-positive clones share a higher ability to grow fibers and an activation of synapsin I expression compared to the parental cells. Atropine, a muscarinic antagonist, abolishes the higher ability to grow fibers of ChAT-positive transfected clones, and the cholinergic agonist carbachol induces higher neurite outgrowth in the parental line. In transient transfections of ChAT-positive clones, the expression of a reporter gene under the control of synapsin I promoter is considerably reduced by atropine, while it is not modified by carbachol; in contrast, in the parental cells, which do not synthesize acetylcholine, the reporter gene expression is induced by carbachol and this effect is abolished by atropine. The data presented provide evidence for the existence of a direct modulation of fiber outgrowth and synapsin I expression by muscarinic receptor activation, which may be related to early growth response gene-1 (EGR-1) levels.  相似文献   
46.
Penile HPV-associated lesions are frequently seen in male sexual partners of women with CIN. The natural course and clinical significance of these lesions are unclear. Women with CIN and their male sexual partners were randomized for condom use (condom group n = 68, noncondom group n = 68). Males were screened for the presence of penile lesions, i.e., flat lesions, papular lesions and condylomata acuminata, and of HPV in their penile swabs by PCR testing. Median follow-up time was 13.1 months (range 2.9-57.4). The outcome of our study was clinical regression of penile lesions defined as disappearance of lesions at penoscopy. Potentially prognostic factors, i.e., HPV status, lesion type and age, were studied as well. Outcomes were assessed in 57 men of the condom group and in 43 men of the noncondom group. Condom use shortened the median time to regression of flat penile lesions (7.4 months condom group vs. 13.9 months noncondom group; HR = 2.1, 95% CI 1.2-3.7). This effect was not found for papular lesions (HR = 0.5, 95% CI 0.1-2.8). HPV-negative men showed a significantly shorter median time to regression of flat lesions (3.8 months) compared to men with either HPV-positive status (8.5 months; HR = 0.4, 95% CI 0.2-0.9) or inconsistent HPV status (13.1 months; HR = 0.2, 95% CI 0.1-0.6). Regression of flat penile lesions is HPV-dependent and accelerated by condom use. This effect is probably the result of blocking viral transmission between sexual partners.  相似文献   
47.
C1-inhibitor (C1-Inh) is an important regulator of inflammatory reactions because it is a potent inhibitor of the contact and complement system. C1-Inh application in inflammatory disease is, however, restricted because of the high doses required. The glycosaminoglycan-like molecule dextran sulphate (DXS) enhances C1-Inh function in vitro. Hence, we investigated whether co-administration with dextran sulphate reduces the amount of C1-Inh required, through enhancement in vivo. C1-Inh potentiation was measured in a newly developed C1s-inactivation assay that is based on activation of C4 by purified C1s. Activated C4 in rat plasma was quantified with a newly developed ELISA. Human C1-Inh (2.5 microM) inhibited C1s in rat plasma 55-fold faster in the presence of dextran sulphate (15 kDa, 5 microM). To study the stability of the complex in vivo, rats were given a mixture of C1-Inh (10 mg/kg) and dextran sulphate (3 mg/kg). C1-Inh activity during 5 h was analyzed ex vivo with the C1s inactivation assay. The noncovalent C1-Inh-dextran sulphate complex resulted in a transient enhancement of the inhibitory capacity of C1-Inh, lasting for 60-90 min. Dextran sulphate did not affect plasma clearance of C1-Inh. We conclude that the enhanced inhibitory capacity of C1-Inh complexed to dextran sulphate is transient in vivo. Hence, co-administration of these compounds seems a feasible approach to achieve short-term inhibition of complement in vivo.  相似文献   
48.
A comparative study on gestational age assessment of 155 newborn infants was undertaken using a scoring system with the clinical criteria: (1) criteria of Dubowitz et al, (2) external criteria alone, and (3) primitive reflexes in relation to the amniotic fluid study. The effect of certain prenatal and perinatal abnormal states on the results of these methods was evaluated. The criteria of Dubowitz et al, external criteria and amniotic fluid studv showed greater accuracy than the primitive reflexes for the assessment of gestational age of normal infants, especially the preterm group. In asphyxiated babies and in babies of diabetic mothers, the neurological score, being poor, under-estimated the gestational age. The amniotic fluid score and the external criteria were more helpful than the neurological score for the assessment of gestational age in these states. Smoking and toxemia did not influence the score by any of the methods in normal infants. In dysmaturity, the amniotic fluid score and score by primitive reflexes were more reliable than the external criteria alone and the criteria of Dubowitz et al. In general, the amniotic fluid score was not influenced by abnormal states compared to scores by other methods.  相似文献   
49.
50.
Intravenous administration of certain immunoglobulin preparations may cause severe adverse reactions, especially in immunodeficient patients. These reactions are generally assumed to be related to the anticomplementary activity of the preparations, caused by IgG aggregates. Because the exact mechanism of the adverse reaction is unknown, we investigated the reactions induced in anesthetized rats on rapid intravenous administration of different human immunoglobulin preparations. The most conspicuous observation was a severe, long-lasting hypotension, induced by standard immunoglobulin preparations (for intramuscular use), which appeared to be independent from the concomitant complement and neutrophil activation. The long-lasting hypotension was not related to the presence of prekallikrein activator, which induced a transient hypotensive reaction only after sensitizing the rats to bradykinin. The reactions appeared to be associated with IgG aggregates. It was found that certain aggregates induced mainly complement activation, whereas others had mainly a hypotensive effect or no effect at all. It was concluded that the rat model provides a sensitive and reproducible test system for vasoactive properties of immunoglobulin preparations for intravenous administration that cannot be predicted from in vitro measurements, such as anticomplementary activity, aggregate content or prekallikrein activator activity. It is suggested that the test may also be used for other plasma products for intravenous administration.  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