全文获取类型
收费全文 | 5290篇 |
免费 | 568篇 |
国内免费 | 69篇 |
专业分类
耳鼻咽喉 | 108篇 |
儿科学 | 130篇 |
妇产科学 | 45篇 |
基础医学 | 741篇 |
口腔科学 | 86篇 |
临床医学 | 659篇 |
内科学 | 1246篇 |
皮肤病学 | 57篇 |
神经病学 | 522篇 |
特种医学 | 442篇 |
外科学 | 645篇 |
综合类 | 116篇 |
一般理论 | 3篇 |
预防医学 | 372篇 |
眼科学 | 55篇 |
药学 | 433篇 |
中国医学 | 1篇 |
肿瘤学 | 266篇 |
出版年
2021年 | 53篇 |
2019年 | 53篇 |
2018年 | 57篇 |
2017年 | 46篇 |
2016年 | 63篇 |
2015年 | 70篇 |
2014年 | 97篇 |
2013年 | 154篇 |
2012年 | 194篇 |
2011年 | 190篇 |
2010年 | 124篇 |
2009年 | 127篇 |
2008年 | 160篇 |
2007年 | 210篇 |
2006年 | 204篇 |
2005年 | 237篇 |
2004年 | 205篇 |
2003年 | 218篇 |
2002年 | 176篇 |
2001年 | 227篇 |
2000年 | 203篇 |
1999年 | 192篇 |
1998年 | 111篇 |
1997年 | 115篇 |
1996年 | 106篇 |
1995年 | 121篇 |
1994年 | 85篇 |
1993年 | 76篇 |
1992年 | 146篇 |
1991年 | 130篇 |
1990年 | 134篇 |
1989年 | 147篇 |
1988年 | 136篇 |
1987年 | 133篇 |
1986年 | 97篇 |
1985年 | 110篇 |
1984年 | 68篇 |
1983年 | 70篇 |
1982年 | 55篇 |
1981年 | 58篇 |
1980年 | 65篇 |
1979年 | 54篇 |
1978年 | 67篇 |
1977年 | 59篇 |
1976年 | 44篇 |
1975年 | 41篇 |
1974年 | 40篇 |
1973年 | 51篇 |
1972年 | 35篇 |
1967年 | 39篇 |
排序方式: 共有5927条查询结果,搜索用时 0 毫秒
31.
32.
Abstract: Low and high resolution sequence specific oligonucleotide probe hybridization patterns were used to design an approach to direct sequencing of allele specific amplified cDNA. Several PCR amplifications were used to derive overlapping sequence fragments to define complete first domain sequences for a single allele. This method has been used to characterize three new DRB1 alleles in the DR52 family, DRB1*1115, DRB1* 1117, and DRB1*1319. All three alleles carry polymorphisms previously observed in other DRB alleles and underscore the importance of utilizing a directed sequencing approach for obtaining unambiguous typing results in matching for bone marrow transplantation between unrelated donor and recipient. 相似文献
33.
34.
Inhibition of inducible nitric oxide synthase expression by interleukin-4 and interleukin-13 in human lung epithelial cells. 总被引:4,自引:0,他引:4 下载免费PDF全文
N Berkman A Robichaud R A Robbins G Roesems E B Haddad P J Barnes K F Chung 《Immunology》1996,89(3):363-367
Oral feeding of proteins causes peripheral T-cell tolerance, as revealed by reduced delayed-type hypersensitivity (DTH) reactivity after immunization. This type of tolerance can be due both to passive T-cell anergy and active immunosuppression. Using ovalbumin-fed mice we studied whether putatively immunostimulatory cytokines could break this state of mucosal tolerance. Cytokines were administered locally at the site of attempted sensitization. It was found that neither interleukin-2 (IL-2), interferon-gamma (IFN-gamma) nor granulocyte-macrophage colony-stimulating factor (GM-CSF) could restore the response to immunization. In contrast, local administration of IL-12 at the site of attempted immunization resulted in full recovery of DTH reactivity. The dichotomy between the two Th1 stimulatory cytokines IFN-gamma and IL-12 was also reflected by different effects on ovalbumin-specific antibody isotypes. Although both IFN-gamma and IL-12 downregulated serum IgG1-levels in tolerant mice, suggesting decreased ovalbumin-specific Th2 function, only local administration of IL-12 led to increased serum IgG2a levels. These results support the view that potentiation of Th1 effector function is critical for reversal of mucosal tolerance. 相似文献
35.
36.
37.
Polysaccharides of the Genus Bacillus Cross-Reactive with the Capsular Polysaccharides of Diplococcus pneumoniae Type III, Haemophilus influenzae Type b, and Neisseria meningitidis Group A 下载免费PDF全文
We studied 174 strains of the genus Bacillus for cross-reacting antigens to the capsular polysaccharides of groups A and C meningococcus, types I and III pneumococcus, and Haemophilus influenzae type b. Cross-reactions were detected by immunodiffusion in agarose gel by using type-specific antisera and confirmed by absorption and inhibition experiments. Of 20 Bacillus pumilis strains, six had an antigen cross-reacting with group A meningococcal polysaccharide. Other cross-reactions included one strain of B. pumilis with H. influenzae type b, one of B. cereus var. mycoides with pneumococcus type III, and one of B. alvei with both type b and SIII polysaccharides. These cross-reacting antigens are polysaccharides of vegetative cells and may be extracellular in location. Because these bacilli have antigens cross-reacting with the virulence factors of pyogenic bacteria, they may, as normal flora, be an antigenic stimulus for "natural" serum anti-capsular antibodies to the type b Haemophilus and group A meningococcus polysaccharides. 相似文献
38.
Running-related injury prevention through barefoot adaptations 总被引:3,自引:0,他引:3
A number of reports indicate an extremely low running-related injury frequency in barefoot populations in contrast to reports about shod populations. It is hypothesized that the adaptations which produce shock absorption, an inherent consequence of barefoot activity and a mechanism responsible for the low injury frequency in unshod populations, are related to deflection of the medial longitudinal arch of the foot on loading. It is also hypothesized that the known inability of this arch of the shod foot to deflect without failure (foot rigidity) is responsible for the high injury frequency in shod populations. To evaluate these hypotheses, 17 recreational runners were analyzed to study the adaptive pattern of the medial longitudinal arch of the foot due to increased barefoot weight-bearing activity. Changes occurred in the medial longitudinal arch which allowed deflection of this arch on loading which substantiated the hypotheses. Other evidence suggests that sensory feedback largely from the glabrous epithelium of the foot is the element of barefoot activity which induced these adaptations. The sensory insulation inherent in the modern running shoe appears responsible for the high injury frequency associated with running. The injuries are considered "pseudo-neuropathic" in nature. 相似文献
39.