全文获取类型
收费全文 | 436504篇 |
免费 | 35442篇 |
国内免费 | 24022篇 |
专业分类
耳鼻咽喉 | 4442篇 |
儿科学 | 6350篇 |
妇产科学 | 8949篇 |
基础医学 | 57274篇 |
口腔科学 | 8890篇 |
临床医学 | 54055篇 |
内科学 | 70222篇 |
皮肤病学 | 5387篇 |
神经病学 | 25957篇 |
特种医学 | 15748篇 |
外国民族医学 | 216篇 |
外科学 | 49047篇 |
综合类 | 54139篇 |
现状与发展 | 76篇 |
一般理论 | 54篇 |
预防医学 | 27940篇 |
眼科学 | 12258篇 |
药学 | 42366篇 |
334篇 | |
中国医学 | 18127篇 |
肿瘤学 | 34137篇 |
出版年
2023年 | 5266篇 |
2022年 | 13485篇 |
2021年 | 17297篇 |
2020年 | 12581篇 |
2019年 | 11819篇 |
2018年 | 12814篇 |
2017年 | 10951篇 |
2016年 | 10382篇 |
2015年 | 15637篇 |
2014年 | 19433篇 |
2013年 | 17551篇 |
2012年 | 26066篇 |
2011年 | 29288篇 |
2010年 | 17991篇 |
2009年 | 14137篇 |
2008年 | 20158篇 |
2007年 | 20386篇 |
2006年 | 20444篇 |
2005年 | 19767篇 |
2004年 | 13512篇 |
2003年 | 12411篇 |
2002年 | 10985篇 |
2001年 | 13621篇 |
2000年 | 14650篇 |
1999年 | 14234篇 |
1998年 | 7070篇 |
1997年 | 6712篇 |
1996年 | 5222篇 |
1995年 | 4747篇 |
1994年 | 3979篇 |
1993年 | 2834篇 |
1992年 | 6311篇 |
1991年 | 6004篇 |
1990年 | 5498篇 |
1989年 | 5219篇 |
1988年 | 4810篇 |
1987年 | 4431篇 |
1986年 | 4032篇 |
1985年 | 3747篇 |
1984年 | 2483篇 |
1983年 | 2097篇 |
1982年 | 1186篇 |
1979年 | 2102篇 |
1978年 | 1266篇 |
1975年 | 1257篇 |
1974年 | 1460篇 |
1973年 | 1495篇 |
1972年 | 1437篇 |
1971年 | 1299篇 |
1970年 | 1195篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
93.
Z D Daniil E Zintzaras T Kiropoulos A I Papaioannou A Koutsokera A Kastanis K I Gourgoulianis 《The European respiratory journal》2007,30(5):957-964
Pleural effusion is a common complication of various diseases. Conventional methods are not always capable of establishing the cause of pleural effusion, so alternative tests are needed. The aim of this study was to explore means of discriminating between different pleural effusion groups, malignant, parapneumonic and tuberculous, based on the combined function of seven biological markers. Adenosine deaminase (ADA), interferon-gamma, C-reactive protein (CRP), carcinoembryonic antigen, interleukin-6, tumour necrosis factor-alpha and vascular endothelial growth factor concentration levels were measured in pleural fluid from 45 patients with malignant, 15 with parapneumonic and 12 with tuberculous pleural effusion. Receiver operating characteristic curve analysis, multinomial logit modelling and canonical variate analysis were applied to discriminate the pleural effusion groups. The three groups could be discriminated successfully using the measured markers. The most important parameters for discrimination were ADA and CRP concentration levels. An individual with an ADA concentration level of >45 U.L(-1) and a CRP concentration of <4 mg.dL(-1) was more likely to belong to the tuberculous pleural effusion group, whereas one with an ADA concentration level of <40 U.L(-1) and a CRP concentration of >6 mg.dL(-1) was more likely to belong to the parapneumonic pleural effusion group, and one with a CRP concentration of <4 mg.dL(-1) to the malignant pleural effusion group. The combination of adenosine deaminase and C-reactive protein levels might be sufficient for discriminating between the three different groups of exudative pleural effusion: malignant, tuberculous and parapneumonic. 相似文献
94.
95.
P Lipiński Z Jarzabek S Broniek T Zagulski 《International journal of experimental pathology》1991,72(6):623-630
The effect of ferritins from horse (FH) and bovine (FB) spleen and murine liver (FM) on the survival rate of CFW mice lethally infected with Escherichia coli (strain 8440-78 K 80/B) was evaluated. Ferritins given intravenously 24 h before intravenous inoculation of bacteria, protected mice most effectively from death due to infection. The effect was dose dependent. At 500 micrograms of ferritin per mouse, the maximum survival rates were 86% (FH), 81% (FM) and 79% (FB), while only 5% of the control mice survived up to the 30th day. The survival rates of animals injected with bovine serum albumin (BSA) and heat-inactivated FB were 8 and 25%, respectively. Intraperitoneal injection of FB was as effective as intravenous in enhancing the resistance of mice against bacteria. These data provide evidence for the beneficial role of tissue ferritins in nonspecific antibacterial resistance. 相似文献
96.
97.
98.
99.
100.
Welson Wen-Shang Wang Dipankar Das Stephen A McQuarrie Mavanur R Suresh 《European journal of pharmaceutics and biopharmaceutics》2007,65(3):398-405
We have developed a universal ovarian cancer cell targeting vehicle that can deliver biotinylated therapeutic drugs. A single-chain antibody variable domain (scFv) that recognizes the CA125 antigen of ovarian cancer cells was fused with a core-streptavidin domain (core-streptavidin-VL-VH and VL-VH-core-streptavidin orientations) using recombinant DNA technology and then expressed in Escherichia coli using the T7 expression system. The bifunctional fusion protein (bfFp) was expressed in a shaker flask culture, extracted from the periplasmic soluble protein, and affinity purified using an IMAC column. The two distinct activities (biotin binding and anti-CA125) of the bfFp were demonstrated using ELISA, Western blot and confocal laser-scanning microscopy (CLSM). The ELISA method utilized human NIH OVCAR-3 cells along with biotinylated bovine serum albumin (B-BSA) or biotinylated liposomes, whereas, the Western blot involved probing with B-BSA. The CLSM study has shown specificity in binding to the OVCAR-3 cell-line. ELISA and Western blot studies have confirmed the bifunctional activity and specificity. In the presence of bfFp, there was enhanced binding of biotinylated antigen and liposome to OVCAR-3 cells. In contrast, the control EMT6 cells, which do not express the CA125 antigen, showed minimal binding of the bfFp. Consequently, bfFp based targeting of biotinylated therapeutic drugs, proteins, liposomes, or nanoparticles could be an alternative, convenient method to deliver effective therapy to ovarian cancer patients. Peritoneal infusion of the bfFp-therapeutic complex could also be effective in locally targeting the most common site of metastatic spread. 相似文献