全文获取类型
收费全文 | 796712篇 |
免费 | 82499篇 |
国内免费 | 250篇 |
专业分类
879461篇 |
出版年
2018年 | 7936篇 |
2017年 | 7588篇 |
2016年 | 10643篇 |
2015年 | 13463篇 |
2014年 | 16038篇 |
2013年 | 23138篇 |
2012年 | 25998篇 |
2011年 | 26776篇 |
2010年 | 18285篇 |
2009年 | 16905篇 |
2008年 | 23938篇 |
2007年 | 24896篇 |
2006年 | 23263篇 |
2005年 | 22372篇 |
2004年 | 22156篇 |
2003年 | 21309篇 |
2002年 | 20811篇 |
2001年 | 34743篇 |
2000年 | 34203篇 |
1999年 | 27575篇 |
1998年 | 10182篇 |
1997年 | 10266篇 |
1996年 | 9838篇 |
1995年 | 9061篇 |
1994年 | 8722篇 |
1993年 | 8755篇 |
1992年 | 22341篇 |
1991年 | 21917篇 |
1990年 | 21372篇 |
1989年 | 20815篇 |
1988年 | 19082篇 |
1987年 | 18322篇 |
1986年 | 17091篇 |
1985年 | 16954篇 |
1984年 | 13934篇 |
1983年 | 12186篇 |
1982年 | 9235篇 |
1981年 | 8355篇 |
1980年 | 7754篇 |
1979年 | 12938篇 |
1978年 | 10203篇 |
1977年 | 9191篇 |
1976年 | 8803篇 |
1975年 | 9818篇 |
1974年 | 10485篇 |
1973年 | 10352篇 |
1972年 | 9477篇 |
1971年 | 8457篇 |
1970年 | 7384篇 |
1969年 | 7255篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
931.
932.
Nine pairs of polymerase chain reaction (PCR) primers that amplify polymorphic microsatellite loci in the desert locust, Schistocerca gregaria (Forskal), were developed using a magnetic bead‐based enrichment protocol. A sample of 48 locusts collected during the 1993 and 1995 upsurge periods in Eritrea, East Africa, were genotyped. The number of alleles per locus ranged from six to 20; the average was 12.67. Allelic distributions were significantly different between samples from different localities. 相似文献
933.
The morphology of dissociated single cerebellar Purkinje cells obtained from wild-type P1 CD1 mice was assessed in the absence
and in the presence of glia. A dedicated noninvasive technique based on optical microscopy was developed. Image processing
algorithms were implemented to extract metrical features characterizing cell structure and dendritic arborization. The morphological
features were analyzed in order to identify quantitative differences in Purkinje cell morphology due to interactions with
astrocytes. 相似文献
934.
D. Padilla F. Acosta J. A. García F. Real Jose R. Vivas 《Archives of microbiology》2009,191(3):191-198
Hafnia alvei, a Gram negative bacillus related to the Enterobacteriaceae family, is considered an opportunistic pathogen of several animal species and humans. In this communication, we describe
fimbrial-like structures from different strains of H. alvei that cannot be easily ascribed to any of the previously reported fimbrial types in this species (type I or type III). Polymerase
chain reaction (PCR) and immunofluorescence assays were carried out to study fimbriae and flagella in H. alvei strains isolated from different sources. No correlation between the results obtained by PCR and those obtained by phenotypic
methods were found, and the antibodies used gave cross or different recognition patterns of the surface structures present
in these strains. We report as well that strain and growth temperature influence fimbriation and expression of flagella in
human and animal isolates of H. alvei. This study also indicates that the absence of fimbriae have a significant positive influence on the initial adhesion of
H. alvei to human epithelial cells. 相似文献
935.
936.
937.
Ronald J. Roberts H. J. Ball A. L. S. Munro W. M. Shearer 《Journal of fish biology》1971,3(2):221-224
Fourteen fresh run salmon Satmo salar L. with early extant lesions of ulcerative dermal necrosis (UDN) were kept in separate tanks and treated with zinc free malachite green. Ten of the fish were held at 10° C and 4 at 2° C. The treatment precluded infection with Saprolegnia fungus and allowed natural resolution of the lesions. There was a marked difference in rate of healing between warm and cold water conditions.
Histological examination of healing lesions at different stages showed that there was a primary invasion of cuboidal epithelium over the collagen scar followed by a phase of disorganized proliferation which eventually organized itself into normal epithelium. Melanocytes were very obvious in the dermis of healing lesions. 相似文献
Histological examination of healing lesions at different stages showed that there was a primary invasion of cuboidal epithelium over the collagen scar followed by a phase of disorganized proliferation which eventually organized itself into normal epithelium. Melanocytes were very obvious in the dermis of healing lesions. 相似文献
938.
939.
Y Trudelle A Brack A Delmas S Pedoussaut P Rivaille 《International journal of peptide and protein research》1987,30(1):54-60
Sequential poly(Arg-Thr-Lys-Pro) consisting mainly of the repeat of tuftsin Thr-Lys-Pro-Arg was synthesized by condensing the p-nitrophenyl ester of Arg(HCl)-Thr-Lys-(2-Cl-Z)-Pro in the presence of HOBt. Two haptenic sequences of the Pre-S region of hepatitis B virus antigen (10-26 and 39-55) were prepared by solid phase and coupled to polytuftsin via glutaraldehyde. The peptides, either free or coupled to polytuftsin, were administrated to mice and the antisera were assayed by ELISA. Coupling the peptides to the polypeptide significantly improved the anti-peptide antibody titer in Freund complete adjuvant or in NaCl 0.9%. Cross-reaction between antibodies induced by the peptides and the native protein was also improved. Polytuftsin alone is very poorly immunogenic. 相似文献
940.