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481.
Detailed karyological analyses have been made of the five biotypes ofPennisetum pedicellatum
Trin. These biotypes not only differ in some morphological traits but also in their chromosomal characteristics. Biotype-B with
2n = 48 chromosomes shows constancy, while in the other four 2n = 36 and 64 are found to be “floating”. Other numerical variations
include 2n = 42 and 18 chromosomes. Minute karyological differences are not only noted amongst the biotypes, but also there
are variations in the complements within a biotype. Such variations are presumed to be buffered through the apomictic mode
of reproduction. From the morphological and cytological studies, the possibility of separation of biotype-B from the complex
in future has been envisaged. 相似文献
482.
483.
Anju Vasudevan 《Cell Adhesion & Migration》2009,3(2):198-Jun;3(2):198
484.
485.
Background
Arsenic, a major pollutant of water as well as soil, is a known endocrine disruptor, and shows adverse effects on the female reproductive physiology. However, the exact molecular events leading to reproductive dysfunctions as a result of arsenic exposure are yet to be ascertained. This report evaluates the effect and mode of action of chronic oral arsenic exposure on the uterine physiology of mature female albino rats. 相似文献486.
Hypoxia in neonates can lead to biochemical and molecular alterations mediated through changes in neurotransmitters resulting
in permanent damage to brain. In this study, we evaluated the changes in the receptor status of GABAA in the cerebral cortex and brainstem of hypoxic neonatal rats and hypoxic rats supplemented with glucose and oxygen using
binding assays and gene expression of GABAAα1 and GABAAγ5. In the cerebral cortex and brainstem of hypoxic neonatal rats, a significant decrease in GABAA receptors was observed, which accounts for the respiratory inhibition. Hypoxic rats supplemented with glucose alone and with
glucose and oxygen showed a reversal of the GABAA receptors, andGABAAα1 and GABAAγ5 gene expression to control. Glucose acts as an immediate energy source thereby reducing the ATP-depletion-induced increase
in GABA and oxygenation, which helps in encountering anoxia. Resuscitation with oxygen alone was less effective in reversing
the receptor alterations. Thus, the results of this study suggest that reduction in the GABAA receptors functional regulation during hypoxia plays an important role in mediating the brain damage. Glucose alone and glucose
and oxygen supplementation to hypoxic neonatal rats helps in protecting the brain from severe hypoxic damage. 相似文献
487.
Culture, Medicine, and Psychiatry - The experiences of dementia sufferers have rarely been examined in sociological literature. This article seeks to describe the experiences of one Alzheimer's... 相似文献
488.
Santosh Kumar Padhi N. Ganesh Pandian Anju Chadha 《Journal of Molecular Catalysis .B, Enzymatic》2004,29(1-6):25-29
Aromatic β-hydroxy acid esters were found to undergo deracemisation using whole cells of Candida parapsilosis. The conditions for the deracemisation reaction were optimised where 75% isolated yield and >95% enantiomeric excess of the product was achieved. The effect of electron donating as well as electron withdrawing groups present in the standard substrate, ethyl 3-hydroxy 3-phenyl propionate was studied to establish the generality of the reaction. The enantiomeric excess of the product remains high (>95%) irrespective of the different substituents in the para position but substitution at the ortho position obstructs the process. Similarly, ethyl and methyl esters of the standard substrate undergo deracemisation reaction giving high ee of the product, but the benzyl ester of the standard substrate did not undergo deracemisation. 相似文献
489.
Summary The effect of aqueous sodium cyanide has been studied on germination ofC. ternatea andR. minima seeds. The suitable concentration of this chemical accelerates imbibition, germination, and promotes the early growth of the seedlings. The best result is obtained by soaking the seeds for 24 hours in a solution of 100 ppm of sodium cyanide. As concentrations are increased the inhibitory effect becames more and more pronounced leading to the eventual suppression of normal germination and growth of the seeds. The mean germination time of the seeds, treated with effective and critical concentrations of the chemical, is decreased. Light and temperature conditions do not influence the chemical effect on the seeds. 相似文献
490.
Selective substitution in vitro of an intrinsic zinc of Escherichia coli RNA polymerase with various divalent metals 总被引:1,自引:0,他引:1
A simple in vitro substitution method involving a sequential denaturation--reconstitution process was developed to substitute selectively one of the two intrinsic Zn ions in Escherichia coli RNA polymerase with Co, Mn, Ni, or Cu ion. The resultant metal hybrid Co-Zn, Mn-Zn, Ni-Zn, and Cu-Zn RNA polymerases possess 100, 100, 60, and 17% of the enzymatic activity of the reconstituted Zn-Zn enzyme, respectively. The substituted metal was found to be located in the beta subunit of the polymerase which contains the substrate binding site. The biochemical and physical properties of these metal-substituted polymerases were compared with those of the native Zn enzyme. Co-Zn and Ni-Zn core polymerases exhibit characteristic absorption spectra in the near-UV and visible region, while Mn-Zn and Cu-Zn enzymes do not. The Co-Zn enzyme shows two major peaks at 400 nm (epsilon = 3000) and 475 nm (epsilon = 2700), while the Ni-Zn enzyme exhibits a major peak at 462 nm (epsilon = 8000). The difference absorption spectrum of Ni-Zn core polymerase could be perturbed by the addition of substrate ATP but not by UTP in the absence of template and Mg(II) ion. These observations suggest that the substituted metal was located at the initiation site of the enzyme. The various metal hybrid enzymes do not differ appreciably in their abilities to incorporate noncomplementary nucleotide or deoxyribonucleotide into RNA product. It was found, however, that the difference in enzymatic activities of these metal hybrid enzymes resides at least partly in the initiation step of RNA synthesis. 相似文献