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   4491篇
  免费   396篇
  国内免费   10篇
耳鼻咽喉   172篇
儿科学   168篇
妇产科学   98篇
基础医学   554篇
口腔科学   102篇
临床医学   490篇
内科学   814篇
皮肤病学   38篇
神经病学   303篇
特种医学   328篇
外科学   635篇
综合类   135篇
一般理论   5篇
预防医学   419篇
眼科学   47篇
药学   331篇
中国医学   4篇
肿瘤学   254篇
  2021年   60篇
  2020年   46篇
  2019年   56篇
  2018年   68篇
  2017年   51篇
  2016年   67篇
  2015年   57篇
  2014年   75篇
  2013年   137篇
  2012年   209篇
  2011年   201篇
  2010年   117篇
  2009年   118篇
  2008年   159篇
  2007年   151篇
  2006年   168篇
  2005年   169篇
  2004年   126篇
  2003年   157篇
  2002年   105篇
  2001年   121篇
  2000年   125篇
  1999年   130篇
  1998年   84篇
  1997年   72篇
  1996年   55篇
  1995年   53篇
  1994年   57篇
  1993年   51篇
  1992年   98篇
  1991年   105篇
  1990年   109篇
  1989年   111篇
  1988年   113篇
  1987年   103篇
  1986年   116篇
  1985年   84篇
  1984年   80篇
  1983年   59篇
  1982年   48篇
  1981年   57篇
  1980年   45篇
  1979年   77篇
  1978年   62篇
  1977年   56篇
  1976年   48篇
  1974年   51篇
  1973年   41篇
  1968年   39篇
  1967年   36篇
排序方式: 共有4897条查询结果,搜索用时 796 毫秒
51.

Background  

Rheumatoid arthritis (RA) and its accepted animal model, murine collagen-induced arthritis (CIA), are classic autoimmune inflammatory diseases which require proinflammatory cytokine production for pathogenesis. We and others have previously used N, N-dimethylglycine (DMG) and extracts from the New Zealand green-lipped mussel Perna canaliculus (Perna) as potent immunomodulators to modify ongoing immune and/or inflammatory responses.  相似文献   
52.
Rats were trained to press a bar for sucrose reward on a random-interval (RI) schedule and footshock punishment was then introduced for 3-min intrusion periods (signalled by a tone) on an independent RI schedule. Shock intensity was individually adjusted to produce stable intermediate levels of response suppression during the tone for each animal. Groups of animals were then allocated to a number of separate experiments in which they were systemically injected with anxiolytics (chlordiazepoxide HCl or sodium amylobarbitone), GABA antagonists (picrotoxin or bicuculline), the GABAA agonist muscimol, the GABAB agonist baclofen, an antagonist (RO 15-1788) at the benzodiazepine receptor and, an inverse agonist (FG 7142) at this receptor. The results showed that the alleviation of punishment-induced suppression of barpressing produced by chlordiazepoxide was blocked or partially blocked by RO 15-1788, picrotoxin and bicuculline but not by FG 7142; that picrotoxin (but not FG 7142) increased the suppression of responding by punishment; that neither muscimol nor baclofen affected responding on their own, but their combination weakly but reliably released punished responding from suppression; and that the anti-punishment effect of amylobarbitone was unaffected by either picrotoxin or bicuculline, though the barbiturate reversed the punishment-enhancing effect of picrotoxin. These results are discussed in the light of the hypothesis that anxiolytic behavioural effects are due to increased GABAergic inhibition.  相似文献   
53.
54.
55.
Assessment of retinol-binding protein excretion in normal children   总被引:4,自引:0,他引:4  
Retinol-binding protein (RBP) is a low molecular weight protein freely filtered at the glomerulus. The fractional tubular reabsorption of RBP is 99.97% and increased excretion is therefore a sensitive marker of tubular dysfunction. We obtained early-morning urine specimens from 151 well children, from newborn to 16 years of age. RBP was measured using an enzyme-linked immunosorbent assay, albumin by a radioimmunoassay and creatinine by a modified Jaffé reaction. Protein excretion was assessed by calculating the protein: creatinine ratio for early-morning urine samples. We found a fall in both RBP and albumin excretion with increasing age, particularly in the 1st year of life, with a much wider variation in values from the infants studied. The mean excretion of RBP for children aged 0–6 months [51.4 (0.6–4,719) g/mmol] was significantly higher (P<0.001) than the mean for children aged 6 months to 16-years [15.0 (3.8–60) g/mmol]. It has been shown that measurement of tubular proteinuria using the RBP: creatinine ratio is useful in the assessment of children with renal disease and we propose a value two standard deviations above the geometric mean for the age of the patient as an upper limit of normal.  相似文献   
56.
The Terumo Capiox SX18R is a commercially available, low prime, reverse phase, hollow fiber membrane oxygenator. The oxygenator consists of a 1.8 m2 microporous polypropylene hollow fiber bundle, a 2200 cm2 tubular stainless steel heat exchanger, and an open hard shell venous reservoir with integral cardiotomy filter. The Terumo Capiox SX18R oxygenator was evaluated to determine its clinical oxygenating performance. Blood samples were drawn from 25 patients yielding 114 data points. The following parameters were recorded: blood flow, cardiac index, gas flow, gas to blood flow ratio, and oxygen fraction. Samples were assayed for hematocrit, hemoglobin, arterial and venous blood gas values, and venous oxygen saturation. The data and assay results were used to calculate arterial, venous, and membrane gas oxygen content, oxygen transfer, shunt fraction, and oxygen diffusion capacity. The Terumo Capiox SX18R oxygenator performed adequately with sufficient oxygen transfer reserve and carbon dioxide clearance under a variety of clinical conditions for the tested population.  相似文献   
57.
58.
自1994年以来,我院采用改良的尿道拖人术治疗外伤性后尿道狭窄22例,取得满意疗效,现报道如下。l临床资料本组病例均为男性,为严重车祸伤或高处跌伤致骨盆骨折所致,年龄则一46岁,平均35岁。临床症状有尿道四溢血、尿摊留、腹胀、肛周青紫肿胀,有休克者2例,合并直肠损伤2例,磅眈破裂6例。术中发现前列腺尖游离者4例。所有病例不能将导尿管插入膀跳,而均行单纯“耻骨上膀胜造疾术”,有膀脱破裂者行“膀脱破裂修补术”,有直肠损伤者,行“乙状结肠造疫术”。患者于术后3-6个月来院行尿道重建术。术前常规尿道造影,显示膜部尿道狭…  相似文献   
59.
A survey directed to centers offering both pediatric and adult perfusion services was conducted to determine how pediatric cases were distributed among individual perfusionists in their departments. These centers were also asked what they believed the clinical activity level should be for a perfusionist each year to remain proficient in pediatric cardiopulmonary bypass. The questions were asked via e-mail and then followed up with telephone interviews as necessary. Out of the 100 centers contacted, 45 responded to the survey (43 North American, 2 European). Of the forty-five centers, forty-one provided both pediatric and adult perfusion services. Thirty-two centers (78%) offering adult as well as pediatric perfusion services distributed the pediatric caseload to a select group of perfusionists. Nine centers (22%) distributed the pediatric open-heart caseload to the entire staff. From the respondents, the average minimum number of pediatric cases believed necessary to remain proficient in pediatric perfusion was 42.8 cases annually. Centers having dedicated pediatric perfusionists had a slightly higher annual caseload than did those at non-specialized centers, despite practicing at institutions averaging fewer pediatric open-heart cases annually.  相似文献   
60.
Researchers have demonstrated that Black women exhibit a disproportionate risk of ill health. We examined the relationship between psychosocial factors, including economic status, race-based social inequality, gender-based violence, and the health status of 323 Black women between the ages of 18 and 65. Black women from a community sample completed a health survey with open-ended responses. Results indicated that women in lower economic groups are more likely to be treated for allergies (p = < .05) and pelvic inflammatory disease (PID; p = < .01). Women who experienced increased incidents of race-based social inequality received more medical treatments for yeast infections, pregnancy-related problems, allergies, and PID. Those with histories of physical, psychological, and early sexual abuse are more likely to be treated for depression, allergies, yeast infections, and hypertension. In addition, qualitative data examined the process in which economic, race-based social inequality, and gender-based violence contributed to the ill health of Black women. The implications of these findings suggest that understanding the psychosocial context is essential for appropriate clinical practice. Additionally, future research should conceptualize health as a complex interaction of psychosocial risks that have a profound effect on the health status of Black women.  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