全文获取类型
收费全文 | 2263篇 |
免费 | 214篇 |
国内免费 | 2篇 |
出版年
2023年 | 6篇 |
2022年 | 5篇 |
2021年 | 24篇 |
2020年 | 24篇 |
2019年 | 18篇 |
2018年 | 39篇 |
2017年 | 34篇 |
2016年 | 59篇 |
2015年 | 106篇 |
2014年 | 128篇 |
2013年 | 130篇 |
2012年 | 172篇 |
2011年 | 154篇 |
2010年 | 104篇 |
2009年 | 102篇 |
2008年 | 142篇 |
2007年 | 150篇 |
2006年 | 174篇 |
2005年 | 144篇 |
2004年 | 114篇 |
2003年 | 123篇 |
2002年 | 134篇 |
2001年 | 24篇 |
2000年 | 18篇 |
1999年 | 22篇 |
1998年 | 32篇 |
1997年 | 19篇 |
1996年 | 28篇 |
1995年 | 23篇 |
1994年 | 32篇 |
1993年 | 18篇 |
1992年 | 26篇 |
1991年 | 14篇 |
1990年 | 13篇 |
1989年 | 17篇 |
1988年 | 12篇 |
1987年 | 10篇 |
1986年 | 7篇 |
1985年 | 13篇 |
1983年 | 8篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1980年 | 7篇 |
1978年 | 4篇 |
1976年 | 9篇 |
1975年 | 3篇 |
1972年 | 3篇 |
1971年 | 3篇 |
1965年 | 2篇 |
1951年 | 2篇 |
排序方式: 共有2479条查询结果,搜索用时 15 毫秒
1.
2.
Nils Milman Niels Graudal Lillian Staub Nielsen Bjørn Mathiassen Palle Tauris Birgit Lund Jørgen Schøler Kristensen Kirsten Fenger 《Human genetics》1990,85(2):228-232
Summary Pedigree studies were performed based on one Faroese and four Danish probands with overt idiopathic hemochromatosis (IH). The study consisted of HLA typing and determination of biochemical iron status indicators (serum transferrin saturation, serum ferritin). In total, 130 persons were evaluated. The screening identified 6 homozygous (h/h) subjects with preclinical IH, 46 heterozygous (h/n), and 8 normal (n/n) subjects, while 39 subjects were classified as normal or heterozygous (n/h?). One family demonstrated both a homozygous x heterozygous as well as a heterozygous x heterozygous mating. Recombination between the HLA region and IH locus occurred possibly in three subjects in three different families. The significance of detailed screening in families with probands with IH is discussed. 相似文献
3.
Immunohistochemical and physiological studies on various insect photoreceptors have demonstrated that the Na,K-ATPase (sodium pump) is restricted to the nonreceptive nonmicrovillar area of the plasma membrane. Here, we examined the distribution of the Na,K-ATPase in photoreceptor cells of the superposition-type compound eye in the moth Manduca sexta. Using immunofluorescent and immunogold cytochemistry, we show that the Na,K-ATPase is localized to both the nonmicrovillar and the microvillar parts of the plasma membrane. Manduca photoreceptors thus deviate from the common concept that the sodium pump and the molecular components of the photoreceptive machinery reside on different domains of the plasma membrane. 相似文献
4.
Waldemar Künkel Dietrich Berger Siegfried Risch Birgit Wittmann-Bresinsky 《Applied microbiology and biotechnology》1992,36(4):499-502
Summary It has shown that several characteristics of high-producing industrial strains of Penicillium chrysogenum tend to segregate in the course of cultivation (slant-to-slant transfer). Segregation includes a decrease in the yield of penicillin, mean conidial size, mean size of the nuclei, and an increase in the proportion of morphologically wild-type colonies. These lower-producing segregants also have a higher sensitivity against ultraviolet radiation and, as shown by cytofluorometric methods, a lower DNA content in the condia, a decrease in phosphate uptkae and in the activity of extracellular alkaline phosphatases compared to high-producing strains. Obviously, during mutagenesis/selection programmes ploidy mutants have been selected, which entails an increase in the number of genes coding enzymes responsible for penicillin biosynthesis. In the absence of selection pressure these high-producing strains segregate to lower-producing strains by chromosome losses in the course of slant-to-slant transfers.
Offprint requests to: W. Künkel 相似文献
5.
Due to post-translational modifications such as phosphorylation, proteins exist as distinct charge variants. Two-dimensional (2D) gel electrophoresis followed by immunoblotting enables the detection of these isoforms. For their accurate relative quantitation in different samples, a loading control is necessary to compensate for technical errors such as imprecise sample loading or transfer. The study reveals that the combinatory approach of SYPRO Ruby and chemiluminescence-based 2D Western blot analysis exhibits high linearity and excellent reproducibility and is applicable for limited sample amounts. 相似文献
6.
Birgit Dittrich 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1991,161(4):441-449
Summary
Hyperia galba was collected in the waters around Helgoland and in the Weser-Elbe-estuary during autumn. Its mode of life is a temporary but obligatory parasitism. The basal biochemical composition of the adults was analyzed in detail and related to the fresh, dry, and ash-free dry weight as well as sex and body length. Hyperia galba (males/females) consists of 85/86% water; the dry matter contains approximately 64/61% protein, 10/11% lipid, 1.2/1.5% carbohydrate, 10/8% chitin, and 23/23% ash. The analyses of basal elemental composition yielded approximately 38% C, 9% N and 6% H. Under natural conditions, individuals may encounter at least two periods of food shortage during their lives. Therefore, the analyses were carried out on individuals of different developmental stages also under food deprivation. The data are discussed with respect to the special mode of life of the species and compared with those found by other authors in several related crustacean species.Abbreviations
AFDW
ash-free dry weight
-
BL
body length
-
DW
dry weight
-
SD
standard deviation
-
WW
wet weight 相似文献
7.
Martina Inga Kirsch Birgit Hülseweh Christoph Nacke Torsten Rülker Thomas Schirrmann Hans-Jürgen Marschall Michael Hust Stefan Dübel 《BMC biotechnology》2008,8(1):66
Background
Venezuelan equine encephalitis virus (VEEV) belongs to the Alphavirus group. Several species of this family are also pathogenic to humans and are recognized as potential agents of biological warfare and terrorism. The objective of this work was the generation of recombinant antibodies for the detection of VEEV after a potential bioterrorism assault or an natural outbreak of VEEV. 相似文献8.
9.
Birgit Binzenhöfer Robert Biedermann Josef Settele Boris Schröder 《Ecological Research》2008,23(2):259-269
Habitat size, habitat isolation and habitat quality are regarded as the main determinants of butterfly occurrence in fragmented
landscapes. To analyze the relationship between the occurrence of the butterfly Cupido minimus and these factors, patch occupancy of the immature stages in patches of its host plant Anthyllis
vulneraria was studied in the nature reserve Hohe Wann in Bavaria (Germany). In 2001 and 2002, 82 A.
vulneraria patches were surveyed for the presence of C. minimus larvae. The occurrence was largely affected by the size of the food plant patches. In a habitat model that uses multiple logistic
regression, the type of management and habitat connectivity are further determinants of species distribution. Internal and
temporal validation demonstrate the stability and robustness of the developed habitat models. Additionally, it was proved
that the colonization rate of C. minimus was significantly influenced by the distance to the next occupied Anthyllis patch. Concerning long-term survival of (meta-) populations in fragmented landscapes, the results show that lower habitat
quality may be compensated by higher connectivity between host plant patches.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
10.
Chromosome Rearrangements in DICTYOSTELIUM DISCOIDEUM 总被引:3,自引:3,他引:0