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61.
The microtubule associated proteins of goat brain were separated from tubulin on the basis of their thermostability and then
fractionated by chromatography on Sepharose 4B column. Analysis of the fractions by SDS-Polyacrylamide gel electrophoresis
and assay of their tubulin-assembly-promoting activity indicate that this activity resides primarily in the tauproteins (mol.
wt. 55,000–70,000) and a class of even lower molecular weight (25,000–35,000) proteins. Electrophoresis of the microtubule
associated protein fractions separated from tubulin by phosphocellulose chromatography are in agreement with the results obtained
from fractionation on Sepharose 4B columns. 相似文献
62.
The molecular conformation of d1-8-isotestosterone has been determined crystallographically. Crystals of the title compound belong to the space group P21/c with a = 11.449(4), b = 10.962(4), c = 25.860(5) , β = 100.95(4)0, with two molecules in the asymmetric unit. The structure has been refined to a final R value of 0.052 for 2227 reflections. Unlike testosterone, which is a flat molecule, its 8-isomer has a folded conformation. The conformations of the ring-B in the two crystallographically independent molecules (A and B) correspond to the twist form and differ significantly from one another. 相似文献
63.
64.
Binding of [3H]dihydroergokryptine and [3H]dihydroalprenolol to membrane preparations from rat submaxillary gland was measured to characterize the alpha- and beta-adrenergic receptors, respectively. Kinetic analysis of the data revealed a high affinity binding site for each radioligand. Inhibition of binding at each site was stereospecific for the active isomer of the catecholamine used. The greater ability of a beta1 than beta2 specific beta-adrenergic antagonist to displace [3H]dihydroalprenolol binding indicated that this binding site was of the beta1 type. Chemical sympathectomy with reserpine or 6-hydroxydopamine resulted in a significant increase in both [3H]dihydroalprenolol and [3H]dihydroergokryptine binding in the rat submaxillary gland. 3scatchard analysis of the data indicated that these increases in binding were due to a change in total number of binding sites for [3H]dihydroergokryptine and [3H]dihydroalprenolol with little change in apparent affinities. This suggests that changes in alpha- and beta-adrenergic receptor density may be important in the development of supersensitivity in salivary glands after reserpine and 6-hydroxydopamine treatment. 相似文献
65.
R K Banerjee 《European journal of biochemistry》1979,97(1):59-64
An adenosine triphosphatase (ATPase EC 3.6.1.3) was partially purified from myeloblasts of chicken infected with the avian myeloblastosis virus and some of its molecular, catalytic and immunological properties were compared with that of the ATPase purified from the virus. Both the enzymes possessed almost same electrophoretic mobility, molecular weight, S20,w value, substrate specificity, metal-ion requirement, apparent Km value and sensitivity to inhibitors and activator. Evidence also indicated immunological identity of the two enzymes. The insensitivity of this enzyme to rutamycin or ouabain and extreme sensitivity to most of the detergents, trypsin and mercurials are the remarkable properties of this enzyme. 相似文献
66.
Synthetic delta 9-tetrahydrocannabinol (THC) was dissolved in undiluted propylene glycol and administered in daily subcutaneous doses of 15.0, 30.0 or 60.0 mg/kg to pregnant New Zealand white rabbits on days 7--19 of gestation. Maternal food consumption and weight gain were markedly reduced at all dose levels. Embryotoxicity and embryocidal effects were observed in the form of reduced litter weight and number of viable fetuses, respectively, in offspring from pregnant mothers treated with THC. However, on the basis of extensive external, visceral and skeletal examination of all fetuses it may be concluded that THC is not teratogenic in the New Zealand white strain rabbit following subcutaneous administration of doses as high as 60.0 mg/kg/day during the critical period of organogenesis (days 7--19 of gestation). On the other hand, an oral dose of thalidomide (200.0 mg/kg/day), the positive control used in this study, was both embryocidal and teratogenic. 相似文献
67.
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69.
How cells regulate the size of intracellular structures and organelles is a longstanding question. Recent experiments suggest that size control of intracellular structures is achieved through the depletion of a limiting subunit pool in the cytoplasm. While the limiting pool model ensures organelle-to-cell size scaling, it does not provide a mechanism for robust size control of multiple co-existing structures. Here we develop a generalized theory for size-dependent growth of intracellular structures to demonstrate that robust size control of multiple intracellular structures, competing for a limiting subunit pool, is achieved via a negative feedback between the growth rate and the size of the individual structure. This design principle captures size maintenance of a wide variety of subcellular structures, from cytoskeletal filaments to three-dimensional organelles. We identify the feedback motifs for structure size regulation based on known molecular processes, and compare our theory to existing models of size regulation in biological assemblies. Furthermore, we show that positive feedback between structure size and growth rate can lead to bistable size distribution and spontaneous size selection. 相似文献
70.
Chiranjib Banerjee Rajib Bandopadhyay Pratyoosh Shukla 《Indian journal of microbiology》2012,52(4):710-712
A simple agar diffusion method is developed where pure colony of Chlamydomonas sp. CRP7 was isolated from Chlorella sp. CB4 mixtures by passing through agar migration with a light exposure of 6,000 lux for 7 h. The main concept behind it is that Chlamydomonas has flagella and the rhodopsin pigment is attracted towards light. Thus the above two microalgae species can be separated from the mixtures as eye spot serves as a navigator and flagella serves as a propeller for Chlamydomonas spp. Further the genomic DNA was isolated and purified from the above mentioned two species after the separation from the mixtures. PCR amplification was carried out for ITS1, 5.8S and ITS2 regions. The amplified products were sequenced and the sequence analysis confirmed that they belong to Chlamydomonas sp. and Chlorella sp. This is an important augmentation for isolation and separation of microalgae. 相似文献