全文获取类型
收费全文 | 13253篇 |
免费 | 1403篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 100篇 |
儿科学 | 412篇 |
妇产科学 | 259篇 |
基础医学 | 1720篇 |
口腔科学 | 270篇 |
临床医学 | 1641篇 |
内科学 | 2542篇 |
皮肤病学 | 120篇 |
神经病学 | 1259篇 |
特种医学 | 434篇 |
外国民族医学 | 5篇 |
外科学 | 1885篇 |
综合类 | 316篇 |
现状与发展 | 1篇 |
一般理论 | 21篇 |
预防医学 | 1565篇 |
眼科学 | 296篇 |
药学 | 1209篇 |
中国医学 | 4篇 |
肿瘤学 | 618篇 |
出版年
2022年 | 86篇 |
2021年 | 219篇 |
2020年 | 141篇 |
2019年 | 233篇 |
2018年 | 241篇 |
2017年 | 192篇 |
2016年 | 213篇 |
2015年 | 255篇 |
2014年 | 316篇 |
2013年 | 451篇 |
2012年 | 687篇 |
2011年 | 729篇 |
2010年 | 367篇 |
2009年 | 348篇 |
2008年 | 675篇 |
2007年 | 706篇 |
2006年 | 664篇 |
2005年 | 691篇 |
2004年 | 658篇 |
2003年 | 576篇 |
2002年 | 571篇 |
2001年 | 401篇 |
2000年 | 410篇 |
1999年 | 321篇 |
1998年 | 157篇 |
1997年 | 155篇 |
1996年 | 131篇 |
1995年 | 114篇 |
1994年 | 106篇 |
1993年 | 103篇 |
1992年 | 244篇 |
1991年 | 228篇 |
1990年 | 218篇 |
1989年 | 201篇 |
1988年 | 171篇 |
1987年 | 203篇 |
1986年 | 168篇 |
1985年 | 156篇 |
1984年 | 141篇 |
1983年 | 136篇 |
1982年 | 102篇 |
1981年 | 89篇 |
1980年 | 87篇 |
1979年 | 158篇 |
1978年 | 103篇 |
1977年 | 93篇 |
1974年 | 86篇 |
1973年 | 92篇 |
1972年 | 90篇 |
1969年 | 79篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Motor loss and swallowing difficulty after stroke: frequency, recovery, and prognosis. 总被引:8,自引:0,他引:8
Data relating to motor loss and swallowing difficulties in a community sample of 976 patients who suffered an acute stroke have been analysed. About 17% of patients seen within one week had no paralysis; at 6 months 48% of survivors had no paralysis and 9% had severe paralysis. The Motricity Index used to study motor loss related to functional loss and walking ability; it seems to be a simple valid measure of motor loss. Severe paralysis was associated with a high fatality rate, and only 6%-10% of survivors of an initially severe paralysis made a full recovery by 6 months. If severe persisted at 3 weeks, full recovery was not observed. Loss of sitting balance was associated with a poor outcome. Of conscious patients seen within one week, 14% choked on attempting to swallow and a further 28% had abnormal swallowing: this 42% of patients had a high fatality rate. 相似文献
42.
From a review of 131 children with arthrogryposis, we studied 18 patients with hip dislocations. Fourteen patients (10 unilateral, four bilateral) were treated by open reduction. Mean age at surgery was 9.7 months, and follow-up ranged from 9 to 245 months. Range of motion of patients treated by open reduction following the medial approach was greater than in those treated by anterolateral incision and greater than in bilateral cases treated by closed reduction. Acetabular development was satisfactory following the medial approach and there were no re-dislocations, but one hip developed avascular necrosis. 相似文献
43.
Behavioural studies showed that administration of alpha-methyl-p-tyramine (AMT; 10 mg/kg i.p.) to rats 24 hr before treatment with d-amphetamine (AMPHET; 4 mg/kg i.p.) resulted in augmentation of AMPHET-induced stereotype activity. Parallel experiments involving electro-chemical estimation of dopamine metabolites in the striatum showed that the decrease in the concentration of homovanillic acid (HVA) produced by AMPHET (4 mg/kg) was enhanced in AMT (10 mg/kg) pretreated animals. These findings suggest that AMT derived from previous doses of AMPHET may play a role in the phenomena of behavioural augmentation observed after chronic administration of AMPHET. 相似文献
44.
45.
46.
The purpose of this study was to determine the conditions for optimum synergistic efficacy of the two-drug combination of trimetrexate and 5-fluorouracil. Synergistic cell killing of Chinese hamster ovary cells in these clonogenic survival assays was observed only when the cells had been exposed to trimetrexate (25 microM) for 2 to 4 h prior to 5-fluorouracil exposure (either 125 or 250 microM). The schedule dependence of the observed synergy in vitro was closely linked to trimetrexate-induced changes in cellular 5-phosphoribosyl 1-pyrophosphate (PRPP) pools. Exposure to 25 microM trimetrexate induced increases in PRPP pools to 398% and 761% of control values at 2 and 4 h, respectively. Methotrexate (20 microM) also increased Chinese hamster ovary cell PRPP content in a time-dependent fashion to values of 280 and 511% of control after 2 and 4 h of drug exposure. Previous in vivo studies demonstrated a modest degree of therapeutic synergy between trimetrexate and 5-fluorouracil against P388 leukemia. Our in vitro results suggested that the degree of synergy seen in vivo could be increased with appropriate schedule changes. Mice were implanted i.p. with 10(6) P388 leukemia cells on Day 0 and were treated with trimetrexate (every 3 h for eight injections; Days 1, 5, and 9) and 5-fluorouracil (Days 1, 5, and 9) as single agents or in combination on one of two schedules; 5-fluorouracil was administered with either the first or the last of the eight trimetrexate doses on Days 1, 5, and 9. Both treatment regimens demonstrated therapeutic synergy but, as predicted from the in vitro data, the "5-fluorouracil last" was superior to the "5-fluorouracil first" sequence. Treatment with the optimal doses on the "5-fluorouracil last" sequence (trimetrexate, 31; 5-fluorouracil, 33 mg/kg/injection) produced an increased life span of 183% and a net reduction in tumor cell burden of 6.7 logs compared with a 111% increased life span (net reduction in tumor burden of 2.6 logs) produced by the most active of the single agents, 5-fluorouracil. Thus the efficacy of the combination of trimetrexate with 5-fluorouracil was sequence and time dependent both in vitro and in vivo. The synergy, observed in vitro and probably in vivo, was linked to a trimetrexate-induced elevation of intracellular PRPP, thus facilitating the production of 5-fluoropyrimidine nucleotides. These data are similar to the sequence and schedule dependency of the methotrexate/5-fluorouracil combination with important differences.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
47.
Inhibition of Dugbe nairovirus replication by human MxA protein 总被引:6,自引:0,他引:6
Sensitivity to the interferon-induced protein, MxA, has previously been demonstrated for viruses belonging to the Orthobunyavirus, Hantavirus and Phlebovirus genera of the Bunyaviridae family. We have extended these findings to a member of the fourth and remaining genus containing viruses that infect man and other animals, the nairovirus Dugbe virus (DUGV). Indirect immunofluorescence experiments using VA9 cells (Vero cells permanently transfected with MxA cDNA) revealed strongly reduced DUGV antigen expression, suggesting that MxA inhibited DUGV replication. Western and Northern blot analyses showed significantly lower DUGV nucleocapsid (N) protein expression and DUGV genomic RNA, respectively, in the presence of MxA. Viral titres were also reduced by more than two orders of magnitude in VA9 cells compared with control VN36 cells. This finding may have application to nairovirus therapeutics. 相似文献
48.
Owens EB Hinshaw SP Kraemer HC Arnold LE Abikoff HB Cantwell DP Conners CK Elliott G Greenhill LL Hechtman L Hoza B Jensen PS March JS Newcorn JH Pelham WE Severe JB Swanson JM Vitiello B Wells KC Wigal T 《Journal of consulting and clinical psychology》2003,71(3):540-552
Using receiver operating characteristics, the authors examined outcome predictors (variables associated with outcome regardless of treatment) and moderators (variables identifying subgroups with differential treatment effectiveness) in the Multimodal Treatment Study of Children with Attention-Deficit/Hyperactivity Disorder (ADHD; MTA). Treatment response was determined using parent- and teacher-reported ADHD and oppositional defiant symptoms, with levels near or within the normal range indicating excellent response. Among 9 baseline child and family characteristics, none predicted but 3 moderated treatment response. In medication management and combined treatments, parental depressive symptoms and severity of child ADHD were associated with decreased rates of excellent response; when these 2 characteristics were present, below-average child IQ was an additional moderator. No predictors or moderators emerged for behavioral and community comparison treatments. The authors discuss conceptual and clinical implications of research on treatment moderators. 相似文献
49.
50.
Elliott L Heederik D Marshall S Peden D Loomis D 《The Journal of allergy and clinical immunology》2005,116(1):127-132
BACKGROUND: Laboratory animal allergy is a common illness among workers exposed to laboratory animals and can progress to symptoms of asthma. OBJECTIVES: This study evaluates the continuum of disease from allergy symptoms to asthma symptoms in a dynamic cohort of workers exposed to animals in a pharmaceutical company. METHODS: Data arose from annual questionnaires administered to workers in a surveillance program established to monitor exposure to animals and the development of allergy. The life-table method was used to compare asthma-free survival between workers with and without symptoms of allergy. A Cox proportional hazards model was used to examine the effects of covariates on the development of asthma. RESULTS: A total of 603 workers contributed 2527.4 person-years to the study over the 12.3-year period. The probabilities of experiencing asthma symptoms by the 11th year of follow-up were 0.367 for workers with allergy symptoms and 0.052 for those without allergy symptoms. The hazard ratio for asthma symptoms when comparing workers with and without allergy symptoms was 7.39 (95% CI, 3.29-16.60) after adjustment for sex and family history of allergy. Female subjects developed asthma at a rate 3.4 times that of male subjects. CONCLUSIONS: This study supports the hypothesis that laboratory animal allergy symptoms are a major risk factor for the development of asthma. It also suggests a heightened risk of asthma for women who work with laboratory animals, a finding that has not been previously reported. 相似文献