全文获取类型
收费全文 | 4275107篇 |
免费 | 307984篇 |
国内免费 | 10555篇 |
专业分类
耳鼻咽喉 | 58375篇 |
儿科学 | 140678篇 |
妇产科学 | 116122篇 |
基础医学 | 600339篇 |
口腔科学 | 123300篇 |
临床医学 | 395334篇 |
内科学 | 825086篇 |
皮肤病学 | 97187篇 |
神经病学 | 347972篇 |
特种医学 | 163029篇 |
外国民族医学 | 1159篇 |
外科学 | 636433篇 |
综合类 | 96441篇 |
现状与发展 | 9篇 |
一般理论 | 1744篇 |
预防医学 | 340860篇 |
眼科学 | 99031篇 |
药学 | 313010篇 |
14篇 | |
中国医学 | 9012篇 |
肿瘤学 | 228511篇 |
出版年
2019年 | 33788篇 |
2018年 | 47599篇 |
2017年 | 36284篇 |
2016年 | 41262篇 |
2015年 | 46663篇 |
2014年 | 65068篇 |
2013年 | 97918篇 |
2012年 | 131501篇 |
2011年 | 139659篇 |
2010年 | 83713篇 |
2009年 | 79271篇 |
2008年 | 129626篇 |
2007年 | 138052篇 |
2006年 | 139726篇 |
2005年 | 134431篇 |
2004年 | 129208篇 |
2003年 | 124217篇 |
2002年 | 119701篇 |
2001年 | 200129篇 |
2000年 | 205507篇 |
1999年 | 173136篇 |
1998年 | 50729篇 |
1997年 | 44556篇 |
1996年 | 44789篇 |
1995年 | 43323篇 |
1994年 | 39824篇 |
1993年 | 37409篇 |
1992年 | 136406篇 |
1991年 | 132148篇 |
1990年 | 128270篇 |
1989年 | 123818篇 |
1988年 | 113800篇 |
1987年 | 111832篇 |
1986年 | 105447篇 |
1985年 | 100938篇 |
1984年 | 75774篇 |
1983年 | 64388篇 |
1982年 | 38040篇 |
1981年 | 34074篇 |
1979年 | 68233篇 |
1978年 | 48332篇 |
1977年 | 41094篇 |
1976年 | 38356篇 |
1975年 | 40805篇 |
1974年 | 48818篇 |
1973年 | 46832篇 |
1972年 | 43810篇 |
1971年 | 40722篇 |
1970年 | 37630篇 |
1969年 | 35776篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
Factors associated with levels of physical activity at work and during leisure time were analyzed among 577 subjects who had been selected as population controls for a case-control study by random selection from telephone directories. The intensity of physical activity at work was inversely associated with body mass index, the proportion of professionals & managers, consumption of western style breakfast, coffee, butter/margarine, and whisky; and positively associated with rice intake. Frequency of physical activities during leisure time was positively associated with consumption of vegetables, fruits, mushrooms, milk, cheese and coffee, and moderation in eating; and inversely associated with rice intake and the prevalence of gastrointestinal symptoms and medication. The association of physical activity with these factors should be considered in studying its relationship to disease risk. 相似文献
962.
The intent of this study was to determine whether chronic ethanol (EtOH) vapor inhalation, with or without adjunct pyrazole (PYR) administration, was stressful in mice, as defined by increases in plasma corticosterone (CORT) concentration. Mice were randomly assigned to groups differentiated both on the basis of EtOH vapor exposure and the presence or absence of PYR administration. Blood samples for blood EtOH concentration (BEC) and plasma CORT concentration were obtained from mice after 72-96 hours of treatment. Mice were sacrificed after 96 hours of treatment and body and adrenal weight determined. BEC was significantly higher in PYR-treated animals and animals treated with the higher EtOH vapor concentration. Plasma CORT was elevated in proportion to BEC; however, other nonspecific stresses, in particular that of PYR administration, also elevated plasma CORT. Nonspecific stresses associated with this protocol may reduce the generality of these observations. Nevertheless, the high correlation between BEC and plasma CORT concentration in the PYR groups indicates that, with suitable control groups, the PYR-EtOH vapor inhalation approach is viable for studies concerned with EtOH effects on hypothalamic-anterior pituitary-adrenocortical function. 相似文献
963.
In 1985 an outbreak of ornithosis affected 13 of 80 (16%) workers in a duck-processing plant. New employees were three times more likely to become cases than established employees. The highest attack rate was in those on the production line. Following the outbreak, an occupational health scheme was set up to monitor the health of new recruits to the company. Serological evidence of recent infection was demonstrated in 18 of 37 (49%) new employees tested in the first 3 months of employment. Five (14%) also had clinical evidence of ornithosis. Veterinary investigation of the ducks demonstrated a high proportion with asymptomatic chlamydial infection. It is suggested that ornithosis may be more common in duck processors than is currently supposed. Strategies to reduce occupational risks are discussed. 相似文献
964.
F Rulli M Muzi M Lazzari M L Capitanucci P Cipriani A Giordano A Magni 《Journal of chemotherapy (Florence, Italy)》1992,4(4):216-220
Pulmonary infection complicating intra-abdominal sepsis is a major clinical problem. An experimental model for intra-abdominal sepsis was created with implantation of gelatin capsules, containing 3 x 10(8) cfu E. coli strain no. 2554, in the peritoneal cavity of 20 rats (10 animals received and 10 did not receive antibiotic therapy with ceftriaxone) in order to verify the role of the primary site of infection in the pathogenesis of pneumonia. Ten rats were sacrificed to determine the relative pulmonary weight and 10 were submitted to simple laparotomy and insertion of a germ-free capsule (sham-operated group). In this group of animals there was only one death (10%). All the rats that received antibiotic therapy survived until sacrifice while all the rats that did not receive ceftriaxone died, 7 within the 2nd and 3 on the 6th postoperative day. Pneumonia and peritonitis developed only in the animals that did not receive ceftriaxone. Bacteriological findings of material obtained from peritoneal and pleural cavities revealed the same strain of E. coli used for the experiment, suggesting that bacteria involved in the pleuro-pulmonary infections may originate in the primary site of infection and that antibiotic therapy started at the moment of contamination, can prevent this major complication. 相似文献
965.
966.
Two-color flow cytometry was carried out to determine the correlation between cell-mediated immunity and the levels of proteinuria in 30 patients with membranous nephropathy. Lymphocyte subpopulations were measured by two-color flow cytometry using various monoclonal antibodies of the Leu series. Clinically, the patients were divided into four stages as follows: 1. untreated nephrotic stage, 2. prednisolone (PSL) treated nephrotic stage, 3. persistent proteinuric stage (incomplete remission, ICR) and 4. complete remission (CR). Two-color flow cytometry showed a significant decrease in Leu 2a+15+ (suppressor T) cells and relative increase in Leu 3a+8+ (suppressor inducer T) cells in the untreated nephrotic stage. The mean Leu 3a+8-/Leu 2a+15+ (helper/suppressor) cell ratio was normalized in the persistent proteinuric stage or complete remission after treatment with PSL. Patients with membranous nephropathy showed a significant elevation of Leu 2a+DR+ cells after treatment with PSL. The abnormalities of suppressor T cells and suppressor inducer T cells in the peripheral blood appear to reflect the levels of proteinuria in patients with membranous nephropathy. It was concluded that PSL might stimulate Leu 2a positive cells and then increase the number of Leu 2a+15+ cells in the peripheral blood of patients with membranous nephropathy. 相似文献
967.
968.
LUMBOVERTEBRAL SYNDROME AFTER EXTRADURAL BLOOD PATCH 总被引:2,自引:1,他引:1
We describe a patient who developed an immobilizing lumbovertebralsyndrome after an extradural blood patch and who was hospitalizedwith a. suspected extradural abscess. An infectious aetiologyof the persistent backache could be excluded and the patientrecovered with analgesics and physiotherapy. The probable aetiologyis discussed. 相似文献
969.
The purpose of this study was to measure the muscle activity during performance of the anti-G straining maneuver (AGSM) at high sustained acceleration stress (+Gz = head-to-foot inertial loading). Ten males were exposed on three separation occasions to a rapid onset rate of 6 + Gz. Subjects wore standard United States Air Force (USAF) anti-G trousers and performed the AGSM until perceived fatigue or until achieving light loss criteria. During each exposure, surface electromyography (EMG) was recorded from the erector spinae, external oblique, bicep femoris, vastus lateralis, and lateral gastrocnemius muscles. The normalized root-mean squares (RMS) and mean power frequency (MPF) for each muscle were calculated and tested for significant differences with an analysis of variance (ANOVA) procedure. The results of this study showed that mean amplitude decreased during the AGSM (35.40%) while MPF showed no significant change. The EMG amplitude of lower extremity muscles decreased (61.45%) while the amplitude of trunk muscles decreased slightly (3.45%). These results indicate that during the performance of the AGSM, motor unit recruitment in lower extremity muscles decrease without evidence of fatigue. 相似文献
970.