全文获取类型
收费全文 | 606篇 |
免费 | 19篇 |
国内免费 | 1篇 |
出版年
2013年 | 10篇 |
2012年 | 11篇 |
2011年 | 18篇 |
2010年 | 38篇 |
2009年 | 41篇 |
2008年 | 29篇 |
2007年 | 36篇 |
2006年 | 21篇 |
2005年 | 11篇 |
2004年 | 12篇 |
2003年 | 6篇 |
2001年 | 6篇 |
2000年 | 6篇 |
1998年 | 11篇 |
1997年 | 14篇 |
1996年 | 10篇 |
1995年 | 8篇 |
1994年 | 5篇 |
1993年 | 14篇 |
1992年 | 8篇 |
1991年 | 9篇 |
1990年 | 5篇 |
1989年 | 6篇 |
1988年 | 16篇 |
1987年 | 9篇 |
1986年 | 7篇 |
1984年 | 9篇 |
1983年 | 8篇 |
1982年 | 6篇 |
1980年 | 11篇 |
1979年 | 8篇 |
1977年 | 5篇 |
1974年 | 4篇 |
1973年 | 6篇 |
1972年 | 5篇 |
1971年 | 7篇 |
1969年 | 5篇 |
1959年 | 8篇 |
1958年 | 16篇 |
1957年 | 17篇 |
1956年 | 16篇 |
1955年 | 8篇 |
1954年 | 13篇 |
1953年 | 18篇 |
1952年 | 9篇 |
1951年 | 10篇 |
1950年 | 12篇 |
1949年 | 3篇 |
1948年 | 8篇 |
1946年 | 3篇 |
排序方式: 共有626条查询结果,搜索用时 109 毫秒
11.
Longitudinal data analysis using generalized linear models 总被引:186,自引:0,他引:186
12.
Trifluralin inhibited root elongation and induced root tip swellingof Zea mays and Triticum aeslivum. Time-course experiments showedthese effects occurred within 6 hr of treatment. As the rootstreated with trifluralin enlarged, there was a concomitant increasein root growth inhibition. Bioassays were devised to quantitativelymeasure the radial enlargement of trifluralin-treated roots.Histological observations indicated that swollen root tissuewas growing in a non-polar manner. The root swelling effectof trifluralin was inhibited 70% by the reducing agent, 2,3-dimercaptopropanol.Trifluralin had no effect on SH content of root tip proteinof Z.mays.
1 Published with the approval of the Director of die West VirginiaAgricultural Experiment Station as Scientific paper No. 1177.
2 Present address: Department of Biology, Mercyhurst College,Erie, Pennsylvania 16501, U.S.A. (Received March 19, 1971; ) 相似文献
13.
The Structure of Calf Liver Cytochrome <Emphasis Type="Italic">b</Emphasis><Subscript>5</Subscript> at 2.8 Å Resolution 总被引:5,自引:0,他引:5
CYTOCHROME b5 is a haem-containing protein in the microsomes of liver tissue. It interacts specifically with a flavo-protein, cytochrome b5 reductase, which catalyses the transfer of electrons from NADH to the haem iron of the cytochrome1. The microsomal cytochrome b5 system has been implicated in fatty acid desaturation reactions2 and a similar system in erythrocytes may catalyse the reduction of methaemoglobin3. Calf liver cytochrome b5, solubilized by pancreatic lipase, has a molecular weight of 11,000 and consists of ninety-three amino-acids in the sequence shown in Fig. 1 (refs. 4 and 5). The haem group is non-covalently bound to the protein and can be removed reversibly by acid acetone treatment6. 相似文献
14.
Agonistic Behavior of Mice and Rats: A Review 总被引:1,自引:0,他引:1
This paper reviews the results of research on the agonisticbehavior of wild and tame strains of house mice (Mus musculus)and the Norway rat (Rattus norvegicus) and covers papers thathave appeared since an earlier review (Scott and Fredericson,1951) Various methods for observing, measuring, and eliciting fightingare described and their appropriate uses discussed. Measuresof latency and frequency are more satisfactory than arbitraryrating scales. Situations involving competition over food presentcomplex motivational problems. The basic agonistic behavior patterns (ethograms) of rats andmice are compared. Differences appear in the lack of playfulfighting and weaning threats in mice, the dual "boxing" postureof rats, and the unique "tail rattling" in mice. Both speciesare alike in their inability to form complex dominance hierarchiesin which fighting is reduced to threat and avoidance. As a general theory, each species has evolved behavior patternsand physiological mechanisms of behavior which are adaptivelyrelated to its own social organization and population dynamics.Mice and rats have evolved along different lines both from eachother and other species of mammals. 相似文献
15.
SCOTT COOK 《American anthropologist》1966,68(2):323-345
"Analytic work begins with material provided by our vision of things, and this vision is ideological almost by definition. It embodies the picture of things as we see them, and wherever there is any possible motive for wishing to see them in a given rather than another light, the way in which we see things can hardly be distinguished from the nay in which we wish to see them. The more honest and naive our vision is, the more dangerous it is to the eventual emergence of anything for which general validity can be claimed. The inference for the social sciences is obvious, antl it is not even true that he who hates a social system will form an objectively more correct vision of it than he who loves it. For love distorts indeed, but hate distorts still more." 相似文献
16.
MARDER EVE; ABBOTT LAURENCE F.; BUCHHOLTZ FRANK; EPSTEIN IRVING R.; GOLOWASCH JORGE; HOOPER SCOTT L.; KEPLER THOMAS B. 《Integrative and comparative biology》1993,33(1):29-39
SYNOPSIS. The stomatogastric nervous system of decapod crustaceansis an ideal system for the study of the processes underlyingthe generation of rhythmic movements by the nervous system.In this chapter we review recent work that uses mathematicalanalyses and computer simulations to understand: 1) the roleof individual currents in controlling the activity of neurons,and 2) the effects of electrical coupling on the activity ofneuronal oscillators. The aim of this review is to highlight,for the physiologist, what these studies have taught us aboutthe organization and function of single cell and multicellularneuronal oscillators. 相似文献
17.
18.
19.
20.