全文获取类型
收费全文 | 227篇 |
免费 | 9篇 |
出版年
2021年 | 2篇 |
2020年 | 3篇 |
2019年 | 1篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 8篇 |
2014年 | 7篇 |
2013年 | 8篇 |
2012年 | 12篇 |
2011年 | 13篇 |
2010年 | 8篇 |
2009年 | 11篇 |
2008年 | 8篇 |
2007年 | 15篇 |
2006年 | 8篇 |
2005年 | 10篇 |
2004年 | 7篇 |
2003年 | 6篇 |
2002年 | 14篇 |
2001年 | 11篇 |
2000年 | 6篇 |
1999年 | 9篇 |
1998年 | 3篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 8篇 |
1991年 | 5篇 |
1990年 | 6篇 |
1989年 | 3篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1968年 | 3篇 |
1967年 | 2篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有236条查询结果,搜索用时 15 毫秒
41.
Monika Martiniaková Radoslav Omelka Birgit Grosskopf Hana Chovancová Peter Massányi Peter Chrenek 《Acta veterinaria Scandinavica》2009,51(1):52
Background
Nickel (Ni) and zinc (Zn) are trace elements present at low concentrations in agroecosystems. Nickel, however, may have toxic effects on living organisms and is often considered as a contaminant. This study reports the effect of peroral administrated Ni or a combination of Ni and Zn on femoral bone structure in rabbits. 相似文献42.
Reduction of indicator and pathogenic microorganisms by psychrophilic anaerobic digestion in swine slurries 总被引:1,自引:0,他引:1
The objective of this study was to evaluate the efficiency of a low temperature anaerobic treatment to reduce viable populations of indicator microorganisms (total coliforms, Escherichia coli) and the presence of selected pathogens (Salmonella, Yersinia enterocolitica, Cryptosporidium and Giardia) in swine slurries from different sources. Experiments were carried out in 40 l Sequencing Batch Reactors (SBRs). Experimental results indicated that anaerobic digestion of swine manure slurry at 20 degrees C for 20 days in an intermittently fed SBR: (1) reduced indigenous populations of total coliforms by 97.94-100%; (2) reduced indigenous populations of E. coli by 99.67-100%; (3) resulted in undetectable levels of indigenous strains of Salmonella, Cryptosporidium, and Giardia. It can be considered as a promising method for reducing indigenous indicator and pathogenic microorganisms populations in liquid swine manure slurries. 相似文献
43.
44.
Massé J Piquet-Pellorce C Viet J Guerrier D Pellerin I Deschamps S 《Experimental cell research》2011,317(13):1922-1934
The nuclear zinc finger protein ZFPIP/Zfp462 is an important factor involved in cell division during the early embryonic development of vertebrates. In pluripotent P19 cells, ZFPIP/Zfp462 takes part in cell proliferation, likely via its role in maintaining chromatin structure. To further define the function of ZFPIP/Zfp462 in the mechanisms of pluripotency and cell differentiation, we constructed a stable P19 cell line in which ZFPIP/Zfp462 knockdown is inducible.We report that ZFPIP/Zfp462 was vital for mitosis and self-renewal in pluripotent P19 cells. Its depletion induced substantial decreases in the expression of the pluripotency genes Nanog, Oct4 and Sox2 and was associated with the transient expression of specific neuronal differentiation markers. We also demonstrated that ZFPIP/Zfp462 expression appears to be unnecessary after neuronal differentiation is induced in P19 cells.Taken together, our results strongly suggest that ZFPIP/Zfp462 is a key chromatin factor involved in maintaining P19 pluripotency and in the early mechanisms of neural differentiation but that it is dispensable in differentiated P19 cells. 相似文献
45.
This review consolidates knowledge regarding the extensive genitourinary pathology experienced by taxi cab drivers. Taxi cab, livery, truck, and other drivers all objectively and subjectively may have more voiding dysfunction, infertility, urolithiasis, bladder cancer, and urinary infections as compared with nonprofessional drivers; this is called taxi cab syndrome. Together with governmental and medical assistance, simple interventions—such as education, the addition of taxi relief stations, and possibly the use of sanitary urinary collection devices—to curb the progression of genitourinary disease in taxi drivers should be prospectively studied. It is postulated that many of these interventions may also benefit other groups of occupationally related infrequent voiders.Key words: Taxi cab syndrome, Infrequent voiders syndrome, Occupational hazard, Voiding dysfunction, Prostodynia, Infertility, UrolithiasisIn New York City, where taxi cabs flow like erythrocytes in a vast net of arteries, the drivers, New York’s backbone, often do not have sufficient flow themselves. This article demonstrates how the lack of adequate and accessible bathroom facilities in New York likely accounts for most of the genitourinary pathology that taxi drivers have. In fact, drivers represent only one of many occupations that contribute to voiding dysfunction as a result of inadequate bathroom access or other factors that lead to the inability to void regularly throughout the workday. These drivers represent the ultimate case study on how, using simple interventions, those who move us through New York City at an often bewildering speed may be helped.In the aptly worded article by Gany and colleagues,1 “Every disease…man can get can start in this cab,” the cardiovascular risk factors of New York City taxi cabs are described in great detail. Gany and colleagues followed a cohort of South Asian immigrant taxi drivers, holding focus groups and administering surveys about the drivers’ perceptions of their own cardiovascular health. Musculoskeletal pain, diabetes, hypertension, vision problems, stress, obesity, and constipation were pervasive throughout the group. Additionally, urinary tract issues such as kidney problems, bladder dysfunction, and prostatism were noted. One of the participants attributed his onset of kidney problems to intentional infrequent urination, and said this was mostly “because you don’t have facilities at most places where you can stand and urinate.” Two other drivers with diabetes-induced polyuria also attributed their severe problem with this issue.1 相似文献
46.
47.
48.
Thomas GH; Newbern EC; Korte CC; Bales MA; Muse SV; Clark AG; Kiehart DP 《Molecular biology and evolution》1997,14(12):1285-1295
Many structural, signaling, and adhesion molecules contain tandemly
repeated amino acid motifs. The alpha-actinin/spectrin/dystrophin
superfamily of F-actin-crosslinking proteins contains an array of triple
alpha-helical motifs (spectrin repeats). We present here the complete
sequence of the novel beta-spectrin isoform beta(Heavy)- spectrin (beta H).
The sequence of beta H supports the origin of alpha- and beta-spectrins
from a common ancestor, and we present a novel model for the origin of the
spectrins from a homodimeric actin-crosslinking precursor. The pattern of
similarity between the spectrin repeat units indicates that they have
evolved by a series of nested, nonuniform duplications. Furthermore, the
spectrins and dystrophins clearly have common ancestry, yet the repeat unit
is of a different length in each family. Together, these observations
suggest a dynamic period of increase in repeat number accompanied by
homogenization within each array by concerted evolution. However, today,
there is greater similarity of homologous repeats between species than
there is across repeats within species, suggesting that concerted evolution
ceased some time before the arthropod/vertebrate split. We propose a
two-phase model for the evolution of the spectrin repeat arrays in which an
initial phase of concerted evolution is subsequently retarded as each new
protein becomes constrained to a specific length and the repeats diverge at
the DNA level. This evolutionary model has general applicability to the
origins of the many other proteins that have tandemly repeated motifs.
相似文献
49.
50.
Summary Water-sobuble trypsin specific macroligands were prepared to separate the trypsin -chymotrypsin mixture with affinity-ultrafiltration technique. Soya bean trypsin inhibitor (STI) attached to cyanogen bromideactivated Dextran showed a good selectivity and low non-specific adsorption properties. The experiments performed with STI-Dextran polymer gave a 81% purified trypsin from 50%-50% mixture. 相似文献