全文获取类型
收费全文 | 431852篇 |
免费 | 13699篇 |
国内免费 | 541篇 |
专业分类
耳鼻咽喉 | 4474篇 |
儿科学 | 14560篇 |
妇产科学 | 8494篇 |
基础医学 | 53149篇 |
口腔科学 | 7532篇 |
临床医学 | 32531篇 |
内科学 | 88546篇 |
皮肤病学 | 7708篇 |
神经病学 | 39317篇 |
特种医学 | 16385篇 |
外国民族医学 | 101篇 |
外科学 | 60968篇 |
综合类 | 3531篇 |
现状与发展 | 1篇 |
一般理论 | 70篇 |
预防医学 | 41325篇 |
眼科学 | 7719篇 |
药学 | 27219篇 |
中国医学 | 1417篇 |
肿瘤学 | 31045篇 |
出版年
2023年 | 1444篇 |
2022年 | 1473篇 |
2021年 | 4617篇 |
2020年 | 2600篇 |
2019年 | 4905篇 |
2018年 | 29192篇 |
2017年 | 21813篇 |
2016年 | 23979篇 |
2015年 | 6978篇 |
2014年 | 7631篇 |
2013年 | 11490篇 |
2012年 | 24731篇 |
2011年 | 38077篇 |
2010年 | 27218篇 |
2009年 | 18234篇 |
2008年 | 34109篇 |
2007年 | 37241篇 |
2006年 | 15849篇 |
2005年 | 17305篇 |
2004年 | 17468篇 |
2003年 | 17219篇 |
2002年 | 14693篇 |
2001年 | 6885篇 |
2000年 | 7160篇 |
1999年 | 6241篇 |
1998年 | 1390篇 |
1997年 | 1196篇 |
1996年 | 987篇 |
1995年 | 954篇 |
1994年 | 852篇 |
1992年 | 3441篇 |
1991年 | 3106篇 |
1990年 | 3017篇 |
1989年 | 2697篇 |
1988年 | 2523篇 |
1987年 | 2361篇 |
1986年 | 2211篇 |
1985年 | 2008篇 |
1984年 | 1496篇 |
1983年 | 1256篇 |
1979年 | 1273篇 |
1978年 | 916篇 |
1977年 | 849篇 |
1975年 | 843篇 |
1974年 | 1049篇 |
1973年 | 1029篇 |
1972年 | 980篇 |
1971年 | 954篇 |
1970年 | 903篇 |
1969年 | 967篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Jim Siderov 《Journal of clinical oncology》2003,21(10):2044-5; author reply 2045
22.
Manuel Steiner Andishe Attarbaschi Margit K nig Helmut Gadner Oskar A. Haas Georg Mann 《Pediatric hematology and oncology》2004,22(1):11-16
Constitutional trisomy 21 is the most prominent predisposing factor to childhood leukemia, whereas the t(12;21)(p13;q22) with its molecular genetic counterpart, the TEL/AML1 fusion gene, is the most common acquired chromosomal rearrangement in childhood B-cell precursor (BCP) acute lymphoblastic leukemia (ALL). Thus, it was somewhat surprising that according to the currently available literature the incidence of TEL/AML1+ BCP ALL is extremely low in patients with Down syndrome (DS). To further investigate this issue in a population-based fashion, the authors retrospectively assessed the number of DS patients with a TEL/AML1+ ALL in two consecutive Austrian ALL multicenter trials. Accordingly, they were able to analyze 8 of 10 individuals with DS and a BCP ALL, including 2 who suffered from a TEL/AML1+ leukemia. Based on this observation we concluded that individuals with a constitutional trisomy 21 may have the similar likelihood to develop a TEL/AML1+ leukemia as BCP ALL patients without this specific predisposing factor. 相似文献
23.
M Müller J Grunewald C Olgart H?glund B Dahlén A Eklund H Stridh 《The European respiratory journal》2006,28(3):513-522
The increased number of lymphocytes in airways during an asthmatic response is believed to be the result of increased recruitment of these cells. However, it is possible that a decreased apoptotic rate could also contribute to the increased number. The aim of the present study was to investigate whether allergen airway provocation influences the apoptotic phenotype of lung and peripheral blood lymphocytes (PBL) in subjects with atopic asthma. Bronchoalveolar lavage (BAL) lymphocytes and PBL from 12 asthmatic subjects previously challenged with allergen (n = 7) or saline (n = 5) were exposed to the apoptotic stimulus tributyltin (TBT) in vitro and assayed for apoptosis. Airway allergen provocation resulted in decreased sensitivity of BAL lymphocytes to TBT-induced apoptosis, with 42.2% (range 33.9-62.5%) apoptotic cells before challenge versus 23.5% (range 15.3-42.4%) after challenge, while PBL were unaffected. The increased apoptosis resistance correlated with higher numbers of Bcl-2-expressing lymphocytes. Interestingly, baseline caspase-3-like activity was significantly elevated in viable BAL lymphocytes compared with viable PBL, and was unaltered by allergen exposure. In conclusion, allergen inhalation renders bronchoalveolar lavage lymphocytes more resistant to apoptosis while peripheral blood lymphocytes were not influenced at all, indicating that the apoptotic phenotype of airway lymphocytes may play a role in asthmatic inflammation. 相似文献
24.
Background
In meningitis, the cerebrospinal fluid contains high levels of innate immune molecules (e.g. complement) which are essential to ward off the infectious challenge and to promote the infiltration of phagocytes (neutrophils, monocytes). However, epithelial cells of either the ependymal layer, one of the established niche for adult neural stem cells, or of the choroid plexus may be extremely vulnerable to bystander attack by cytotoxic and cytolytic complement components. 相似文献25.
Lipid peroxidation, occupational stress and aging in workers of a prehospital emergency service. 总被引:2,自引:0,他引:2
Angela Casado Nieves De Lucas Encarnación López-Fernández Alberto Sánchez José-Antonio Jimenez 《European journal of emergency medicine》2006,13(3):165-171
BACKGROUND: Stressful conditions lead to formation of excessive free radicals, and lipid peroxidation is one of the major outcomes of free radical-mediated injury that directly damages membranes and generates a number of secondary products. OBJECTIVES: To determine the levels of malondialdehyde, an end product of lipid peroxidation, according to demographic and occupational variables in workers of a prehospital emergency service and to analyse the relationship between malondialdehyde levels and burnout. MATERIAL AND METHODS: One hundred and eleven healthy workers of a prehospital emergency service and eighty aged-matched healthy individuals of both sexes as a control group were surveyed. Malondialdehyde levels were measured by the Bull and Marnett method. To measure burnout, the Maslach Burnout Inventory was used. RESULTS: Professional category is associated with lipid peroxidation and burnout levels (Malondialdehyde levels were: physicians 338.10+/-14.47, nurses 329.17+/-12.62 and technicians 296.74+/-14.28; burnout levels were: physicians 41.29+/-3.59, nurses 37.38+/-6.05 and technicians 35.33+/-5.87). Working at night and in the evening increased malondialdehyde and burnout levels. Malondialdehyde levels increase with age. No significant variations with respect to sex were detected. Significant variations in malondialdehyde levels were detected between singles (303.13+/-12.74) and married people (344.43+/-13.43) but not with respect to divorcees (326.44+/-11.74). Significant differences were detected in erythrocyte malondialdehyde levels between smokers (341.37+/-17.09) and nonsmokers (302.21+/-12.38), but not for alcohol consumption. CONCLUSIONS: These findings suggest a positive correlation between malondialdehyde, a biomarker of lipid peroxidation and occupational stress, as estimated by elements of the Maslach Burnout Inventory, and oxidative stress. 相似文献
26.
27.
28.
29.
Victor Aboyans Louis Labrousse Philippe Lacroix Jér?me Guilloux Seifeddine Sekkal Alexandre Le Guyader Elisabeth Cornu Marc Laskar 《European journal of cardio-thoracic surgery》2006,30(2):300-304
BACKGROUND: Despite major improvement in surgical techniques and intensive care management, stroke remains one of the most devastating complications of coronary artery bypass grafting (CABG). We aimed to determine factors predicting the occurrence of stroke during CABG. A special interest was focused on preoperative therapies. METHODS: We prospectively enrolled 810 consecutive candidates for CABG alone in a specific database, including all pre- and perioperative data (history, clinical, therapeutic, cardiac catheterization, surgical and intensive care data). Univariate tests and then multiple logistic regression analysis were used to determine independent predictive factors. RESULTS: During the first postoperative month, stroke occurred in 11 cases and transient ischemic attack (TIA) in 4 additive cases (cumulative rate: 1.85%). After the multivariate analysis, the following factors remained significant (p<0.05) in the predictive model, with corresponding odds ratios between brackets: redo cardiac surgery (7.45), unstable cardiac status (4.74), past history of cerebrovascular disease (4.14), past history of peripheral arterial disease (3.55), whereas the presence of preoperative statins was protective (0.24, 95% IC: 0.07-0.78). The addition of perioperative data (aortic calcification, postoperative arrhythmia, on/off-pump surgery) did not change the final predictive model. CONCLUSION: To our knowledge, this is the first real-world observational report highlighting the interest of statins for the prevention of stroke in the very special situation of CABG. Even though according to randomized trials coronary patients have a benefit from these drugs, a special level of interest should be directed towards those presenting the above-mentioned risk factors. 相似文献
30.