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91.
The clerodane diterpenoid salvinorin A (1), the main active component of the psychotropic herb Salvia divinorum, has been reported to be a potent agonist at the kappa-opioid receptor. Computer modeling suggested that splendidin (2) from S. splendens, as well as related compounds, might possess similar activities. In the present study, this hypothesis was tested by determination of the binding properties of a series of structural congeners, compounds 2-8, at the mu-, delta-, and kappa-opioid receptors. However, none of these compounds showed significant binding to any of the opioid-receptor subtypes, thus disproving the above hypothesis. The novel compounds 7 and 8 were obtained semi-synthetically by selective modification of salvifarin (5), isolated from Salvia farinacea, upon epoxide-ring opening with AcOH in the presence of indium(III) triflate. Also, the X-ray crystal structure of salvifaricin (6; Fig.), obtained from S. farinacea, was determined for the first time and used, in combination with in-depth NMR experiments, to elucidate the absolute configurations of the new products. Our experiments demonstrate that the relatively well-accessible diterpenoid 6 could be used as starting material for future studies into the structure-activity relationship at the kappa-opioid receptor. 相似文献
92.
93.
Plant cryopreservation: Progress and prospects 总被引:9,自引:0,他引:9
Summary Cryopreservation (liquid nitrogen, −196°C) represents the only safe and cost-effective option for long-term conservation of
germplasm of non-orthodox seed species, vegetatively propagated species, and of biotechnology products. Classical cryopreservation
techniques, which are based on freeze-induced dehydration, are mainly employed for freezing undifferentiated cultures and
apices of cold-tolerant species. New cryopreservation techniques, which are based on vitrification of internal solutes, are
successfully employed with all explant types, including cells suspensions and calluses, apices, and somatic and zygotic embryos
of temperate and tropical species. The development of cryopreservation protocols is significantly more advanced for vegetatively
propagated species than for recalcitrant seed species. Even though its routine use is still limited, there are a growing number
of examples where cryopreservation is employed on a large scale for different types of materials, including seeds with orthodox
and intermediate storage behaviour, dormant buds, pollen, biotechnology products, and apices sampled from in vitro plantlets of vegetatively propagated species. Cryopreservation can also be employed for uses other than germplasm conservation,
such as cryoselection, i.e., the selection through freezing of samples with special properties, or cryotherapy, i.e., the
elimination of viruses from infected plants through apex cryopreservation. Because of its high potential, it is expected that
cryopreservation will become more frequently employed for long-term conservation of plant genetic resources. 相似文献
94.
95.
Wong L 《Briefings in bioinformatics》2002,3(4):389-404
The process of building a new database relevant to some field of study in biomedicine involves transforming, integrating and cleansing multiple data sources, as well as adding new material and annotations. This paper reviews some of the requirements of a general solution to this data integration problem. Several representative technologies and approaches to data integration in biomedicine are surveyed. Then some interesting features that separate the more general data integration technologies from the more specialised ones are highlighted. 相似文献
96.
Proteomics in biomarker discovery and drug development 总被引:5,自引:0,他引:5
Proteomics is a research field aiming to characterize molecular and cellular dynamics in protein expression and function on a global level. The introduction of proteomics has been greatly broadening our view and accelerating our path in various medical researches. The most significant advantage of proteomics is its ability to examine a whole proteome or sub-proteome in a single experiment so that the protein alterations corresponding to a pathological or biochemical condition at a given time can be considered in an integrated way. Proteomic technology has been extensively used to tackle a wide variety of medical subjects including biomarker discovery and drug development. By complement with other new technique advances in genomics and bioinformatics, proteomics has a great potential to make considerable contribution to biomarker identification and to revolutionize drug development process. This article provides a brief overview of the proteomic technologies and their application in biomarker discovery and drug development. 相似文献
97.
The effects of endogenous and exogenous C2H4 and C2H4 inhibitors on the postharvest leaf and flower quality of Oriental lily Stargazer were investigated. Endogenous C2H4 was not produced by freshly harvested excised leaves or flowers. Treatment of freshly harvested excised flowers, buds, leaves, and intact cut stems with C2H4 concentrations as high as 10 µl·l–1 did not affect bud opening or longevity or the development of leaf yellowing. Therefore, treatment with anti-C2H4 compounds, such as silver thiosulfate (STS) and 1-methylcyclopropene (1-MCP), did not improve the quality of the flowers. Data thus indicate that freshly harvested Stargazer were not sensitive to C2H4. Sensitivity of Stargazer to C2H4, however, increased dramatically following cold storage, as exposure of cold-stored stems to C2H4 concentrations as low as 0.3 µl·l–1 significantly affected bud opening. The development of leaf yellowing on cold-stored stems was not affected by the exogenous C2H4. Pretreating cold-stored stems with 1-MCP significantly reduced blasting of small buds that failed to develop due to carbohydrate depletion and reduced the percentage of buds that did not fully open. Concurrently, 1-MCP did not affect the quality of the leaves. These data indicate that sensitivity of cut lilies to C2H4 differs following cold storage and that 1-MCP is a more suitable anti-C2H4 compound than STS. Furthermore, studies on endogenous C2H4 production revealed that, while C2H4 was not detected in freshly harvested buds and leaves, it was produced by both following cold storage. The latter produced C2H4 at a higher rate than the former. Results of this study clearly indicate that there are two situations in which lilies will benefit from pretreatment with an anti-C2H4 compound (1) when cut stems contain buds that are marginally small for opening and (2) when cut stems will be cold stored before marketing. 相似文献
98.
Walker K 《Medical and veterinary entomology》2000,14(4):345-354
In anti-malaria operations the use of DDT for indoor residual spraying has declined substantially over the past 30years, but this insecticide is still considered valuable for malaria control, mainly because of its low cost relative to alternative insecticides. Despite the development of resistance to DDT in some populations of malaria vector Anopheles mosquitoes (Diptera: Culicidae), DDT remains generally effective when used for house-spraying against most species of Anopheles, due to excitorepellency as well as insecticidal effects. A 1990 cost comparison by the World Health Organization (WHO) found DDT to be considerably less expensive than other insecticides, which cost 2 to 23 times more on the basis of cost per house per 6 months of control. To determine whether such a cost advantage still prevails for DDT, this paper compares recent price quotes from manufacturers and WHO suppliers for DDT and appropriate formulations of nine other insecticides (two carbamates, two organophosphates and five pyrethroids) commonly used for residual house-spraying in malaria control programmes. Based on these 'global' price quotes, detailed calculations show that DDT is still the least expensive insecticide on a cost per house basis, although the price appears to be rising as DDT production declines. At the same time, the prices of pyrethroids are declining, making some only slightly more expensive than DDT at low application dosages. Other costs, including operations (labour), transportation and human safety may also increase the price advantages of DDT and some pyrethroids vs. organophosphates and carbamates, although possible environmental impacts from DDT remain a concern. However, a global cost comparison may not realistically reflect local costs or effective application dosages at the country level. Recent data on insecticide prices paid by the health ministries of individual countries showed that prices of particular insecticides can vary substantially in the open market. Therefore, the most cost-effective insecticide in any given country or region must be determined on a case-by-case basis. Regional coordination of procurement of public health insecticides could improve access to affordable products. 相似文献
99.
Bacillus species and other microbes with pH optima for growth higher than pH 9 are defined as alkaliphiles. A large number of alkaliphilic
Bacillus strains producing useful enzymes, have been isolated from various environments. Some of these enzymes, such as proteases
and cellulases from alkaliphilic Bacillus strains, have been commercialized and have brought great advantages to industry and domestic life. To support further development
of the enzyme industry, we initiated analysis of the genome of Bacillus halodurans C-125, which is 4.25 Mb in size, and constructed a physical and genetic map for comparison with the Bacillus subtilis chromosome. Systematic sequencing of the whole genome of Bacillus halodurans C-125 has been automated since the beginning of May 1998, and sequencing of 98% of the whole genome has been done so far.
Through genome analysis, it became apparent that the genome organization of alkaliphilic Bacillus halodurans C-125 is totally different from that of B. subtilis orthologues.
Received: July 11, 1999 / Accepted: December 27, 1999 相似文献
100.