全文获取类型
收费全文 | 2586篇 |
免费 | 51篇 |
国内免费 | 1篇 |
专业分类
2638篇 |
出版年
2016年 | 23篇 |
2015年 | 30篇 |
2013年 | 50篇 |
2012年 | 46篇 |
2011年 | 48篇 |
2009年 | 21篇 |
2008年 | 45篇 |
2007年 | 28篇 |
2006年 | 30篇 |
2005年 | 37篇 |
2004年 | 41篇 |
2003年 | 35篇 |
2001年 | 23篇 |
2000年 | 17篇 |
1999年 | 18篇 |
1981年 | 18篇 |
1979年 | 19篇 |
1974年 | 28篇 |
1973年 | 33篇 |
1972年 | 32篇 |
1971年 | 21篇 |
1970年 | 20篇 |
1969年 | 32篇 |
1968年 | 32篇 |
1966年 | 23篇 |
1943年 | 24篇 |
1939年 | 18篇 |
1938年 | 17篇 |
1937年 | 23篇 |
1935年 | 23篇 |
1934年 | 19篇 |
1933年 | 16篇 |
1919年 | 17篇 |
1909年 | 25篇 |
1894年 | 26篇 |
1893年 | 17篇 |
1891年 | 19篇 |
1890年 | 24篇 |
1889年 | 20篇 |
1885年 | 19篇 |
1882年 | 20篇 |
1881年 | 17篇 |
1880年 | 26篇 |
1878年 | 21篇 |
1877年 | 22篇 |
1875年 | 20篇 |
1868年 | 16篇 |
1867年 | 20篇 |
1860年 | 17篇 |
1857年 | 17篇 |
排序方式: 共有2638条查询结果,搜索用时 0 毫秒
101.
Vollset Knut Wiik Lennox Robert J. Thorstad Eva B. Auer Samuel Bär Kerstin Larsen Martin H. Mahlum Shad Näslund Joacim Stryhn Henrik Dohoo Ian 《Reviews in Fish Biology and Fisheries》2020,30(4):553-568
Reviews in Fish Biology and Fisheries - A systematic review and meta-analysis was conducted to evaluate the appropriate tag:fish size ratio when tagging juvenile salmonids (genera Oncorhynchus,... 相似文献
102.
Mamoru Arai Masaki Nakahara v Hamano Hiroshi Okazaki 《Bioscience, biotechnology, and biochemistry》2013,77(9):1813-1819
Systematic isolation of the cell constituents of Proteus mirabilis RMS–203 was performed to find out localization of antitumor principle only in the lipopolysaccharide (LPS) layer of the cell wall fraction.LPS with strong antitumor activity was extracted from P. mirabilis RMS–203 by phenol-water method followed by purification on DEAE-Sephadex A–50 column chromatography.The main components of purified LPS were galactose, hexosamine, 2-keto-deoxy-octonic acid (KDO), myristic acid, β-hydroxymyristic acid and α,ε-diaminopimelic acid.The minimal effective dose of LPS against Ehrlich solid carcinoma in mice was 0.1~1.0 μg/mouse. LD50 in mice and pyrogenicity in rabbits were 28 mg/kg and 10?3–10?5 μg/rabbit, respectively. 相似文献
103.
Sørensen GL Hjelmborg Jv Kyvik KO Fenger M Høj A Bendixen C Sørensen TI Holmskov U 《American journal of physiology. Lung cellular and molecular physiology》2006,290(5):L1010-L1017
The collectin surfactant protein D (SP-D) is an important component of the pulmonary innate immune system, but SP-D is also present on extrapulmonary epithelial surfaces and in serum, where it has been used as a biomarker for pulmonary disease states. In this study, we investigate the mechanisms defining the constitutional serum level of SP-D and determine the magnitude of the genetic contribution to serum SP-D in the adult population. Recent studies have demonstrated that serum SP-D concentrations in children are genetically determined and that a single nucleotide polymorphism (SNP) located in the NH(2)-terminal region (Met11Thr) of the mature protein is significantly associated with the serum SP-D levels. A classic twin study was performed on a twin population including 1,476 self-reported healthy adults. The serum SP-D levels increased with male sex, age, and smoking status. The intraclass correlation was significantly higher for monozygotic (MZ) twin pairs than for dizygotic (DZ) twin pairs. Serum SP-D variance was influenced by nonshared environmental effects and additive genetic effects. Multivariate analysis of MZ and DZ covariance matrixes showed significant genetic correlation among serum SP-D and metabolic variables. The Met11Thr variant explained a significant part of the heritability indicating that serum SP-D variance could be decomposed into non-shared environmental effects (e(2) = 0.19), additive genetic effects (h(2) = 0.42), and the effect of the Met11Thr variations (q(2) = 0.39). 相似文献
104.
105.
106.
Dr. Gustav v. Pernhoffer 《Plant Systematics and Evolution》1896,46(5):196-197
Ohne Zusammenfassung 相似文献
107.
108.
109.
Alexandra Myari Gerasimos Malandrinos John Plakatouras Nick Hadjiliadis Imre Sóvágó 《Bioinorganic Chemistry and Applications》2003,1(1):99-112
His-Val-His and His-Val-Gly-Asp are two naturally occurring peptide sequences, present at the active site
of Cu,Zn-superoxide dismutase (Cu,Zn-SOD). We have already studied the interaction of His-Val-His=A
(copper binding site) with Cu(II) and of His-Val-Gly-Asp=B (zinc binding site) with Zn(II). As a
continuation of this work and for comparison purposes we have also studied the interaction of Zn(II) with
His-Val-His and Cu(II) with His-Val-Gly-Asp using both potentiometric and spectroscopic methods (visible,
EPR, NMR). The stoichiometry, stability constants and solution structure of the complexes formed have been
determined. Histamine type of coordination is observed for/ZnAH/2+, /ZnA/+, /ZnA2H/+ and/ZnA2/ in acidic pH while deprotonation of coordinated water molecules is observed at higher pH. /CUB/ species is
characterized by the formation of a macrochelate and histamine type coordination. Its stability results in the
suppression of amide deprotonation which occurs at high pH resulting in the formation of the highly distorted
from square planar geometry 4N complex/CuBH-3/3. 相似文献
110.
Attila óvári Dóra Neményi Tino Just Tobias Schuldt Anne Buhr Robert Mlynski András Csókay Hans-Wilhelm Pau István Valálik 《PloS one》2016,11(3)