全文获取类型
收费全文 | 5160篇 |
免费 | 209篇 |
国内免费 | 1篇 |
出版年
2023年 | 17篇 |
2022年 | 21篇 |
2021年 | 40篇 |
2020年 | 23篇 |
2019年 | 41篇 |
2018年 | 89篇 |
2017年 | 93篇 |
2016年 | 109篇 |
2015年 | 97篇 |
2014年 | 133篇 |
2013年 | 218篇 |
2012年 | 450篇 |
2011年 | 650篇 |
2010年 | 294篇 |
2009年 | 90篇 |
2008年 | 434篇 |
2007年 | 401篇 |
2006年 | 345篇 |
2005年 | 312篇 |
2004年 | 253篇 |
2003年 | 239篇 |
2002年 | 183篇 |
2001年 | 71篇 |
2000年 | 149篇 |
1999年 | 79篇 |
1998年 | 49篇 |
1997年 | 14篇 |
1996年 | 12篇 |
1995年 | 18篇 |
1994年 | 12篇 |
1993年 | 11篇 |
1992年 | 21篇 |
1991年 | 15篇 |
1990年 | 12篇 |
1989年 | 12篇 |
1987年 | 18篇 |
1985年 | 19篇 |
1984年 | 22篇 |
1982年 | 16篇 |
1981年 | 9篇 |
1980年 | 18篇 |
1979年 | 16篇 |
1978年 | 13篇 |
1977年 | 9篇 |
1976年 | 17篇 |
1975年 | 12篇 |
1974年 | 18篇 |
1973年 | 9篇 |
1972年 | 9篇 |
1971年 | 10篇 |
排序方式: 共有5370条查询结果,搜索用时 125 毫秒
101.
102.
Marijana Popović Hadžija Marina Korolija Nikolina Jemin Iva Pavković Pajica Pavković Edita Pape Medvidović Mirko Hadžija 《Gene》2013
Genetic variants of IL-18 and IL-12B may be important in immunoregulatory abnormalities, observed in the patients with Type 1 diabetes mellitus (T1DM), that contribute to individual differences in response to a treatment. Therefore, we examined the significance of IL-18-137G/C, IL-18-607C/A, and IL-12B A/C polymorphisms in Croatians (187 patients, 236 controls), not only as factors that contribute to susceptibility to T1DM, but also as determinants of the clinical presentation of disease. 相似文献
103.
Marija Brgles Darija Jurašin Maja Dutour Sikirić Ruža Frkanec Jelka Tomašić 《Journal of liposome research》2013,23(3):235-248
Various amounts of Ovalbumin (OVA) were encapsulated into positively and negatively charged multilamellar liposomes, with the aim to investigate the entrapment efficiency in different buffers and to study their effects on the liposome size and zeta potential. Results showed that the entrapment efficiency of OVA in anionic liposomes was the same in 10 mM Phosphate Buffer (PB) as in Phosphate-Buffered Saline (PBS; PB?+?0.15 M NaCl). Also, liposome size was approximately 1200 nm for all anionic liposomes incorporating OVA. The entrapment efficiency of OVA in cationic liposomes was highly dependent on ionic strength. The size of cationic liposomes was approximately 1200 nm in PBS, regardless of protein content, but increased with the amount of the incorporated protein in PB. Aggregation of cationic liposomes in PB was observed when the mass of the protein was 2.5 mg or greater. The zeta potential of anionic liposomes was negative and of cationic liposomes positive in the whole range of protein mass tested. These results show how different compositions of lipid and aqueous phases can be used to vary the entrapment efficiency, liposome size, and zeta potential—the factors that are of great importance for the use of liposomes as drug carriers. 相似文献
104.
Željko Tomanović Christos G. Athanassiou Ljubisbrevea Ž. Stanisavljević 《法国昆虫学会纪事》2013,49(4):343-353
A review of aphidiine wasps (Hymenoptera: Braconidae) parasitizing the Uroleucon species in the West Palaearctic is presented. Eleven species are keyed and illustrated. In addition, a new hymenopteran parasitoid species: Praon nonveilleri n. sp. from Uroleucon inulicola (Hille Ris Lambers) infesting Inula ensifolia L., is described. The new species is diagnosed and illustrated. It belongs to the “dorsale-yomenaé” species group and was collected from the Djetinja canyon in Serbia and Montenegro. The aphidiines presented in this work were identified from 97 aphid taxons occurring on 236 plant taxons. Furthermore, 361 original parasitoid – host aphid – host plant associations of the species mentioned in the key are presented. Finally, phylogenetic relationships inside the “dorsale-yomenae” species group and related species were reconstructed using cladistic distance methods. 相似文献
105.
106.
Cedric P. Owens Nicholas Chim Amanda B. Graves Christine A. Harmston Angelina Iniguez Heidi Contreras Matthew D. Liptak Celia W. Goulding 《The Journal of biological chemistry》2013,288(30):21714-21728
Mycobacterium tuberculosis is the causative agent of tuberculosis, which is becoming an increasingly global public health problem due to the rise of drug-resistant strains. While residing in the human host, M. tuberculosis needs to acquire iron for its survival. M. tuberculosis has two iron uptake mechanisms, one that utilizes non-heme iron and another that taps into the vast host heme-iron pool. To date, proteins known to be involved in mycobacterial heme uptake are Rv0203, MmpL3, and MmpL11. Whereas Rv0203 transports heme across the bacterial periplasm or scavenges heme from host heme proteins, MmpL3 and MmpL11 are thought to transport heme across the membrane. In this work, we characterize the heme-binding properties of the predicted extracellular soluble E1 domains of both MmpL3 and MmpL11 utilizing absorption, electron paramagnetic resonance, and magnetic circular dichroism spectroscopic methods. Furthermore, we demonstrate that Rv0203 transfers heme to both MmpL3-E1 and MmpL11-E1 domains at a rate faster than passive heme dissociation from Rv0203. This work elucidates a key step in the mycobacterial uptake of heme, and it may be useful in the development of anti-tuberculosis drugs targeting this pathway. 相似文献
107.
108.
Damir Valić Irena Vardić Smrzlić Damir Kapetanović Zlatica Teskeredžić Bruna Pleše Emin Teskeredžić 《Biologia》2013,68(3):539-545
In order to determine an unknown fish population from the Vrana Lake, mitochondrial cytochrome b gene and non-coding nuclear region Cyfun P were investigated. Stabile population of Bulldog rudd, Scardinius dergle Heckel & Kner, the endemic Croatian freshwater fish in the Krka River, was genetically characterized with the same markers in order to compare it with the material from the Vrana Lake. Genetic markers were sequenced and aligned with the similar ones obtained from the GenBank in order to determine taxonomic and phylogenetic position of these two species. A significant discrepancy between nuclear genetic markers of our specimens and the sequence from the GenBank was found. Phylogenetic analysis suggested that the specimens from the Vrana Lake belong to the species S. hesperidicus. Morphometric characteristics, the maximum length and body mass showed new maximum values for both S. dergle and S. hesperidicus. 相似文献
109.
Małgorzata Proćków Magda Drvotová Lucie Juřičková Elżbieta Kuźnik-Kowalska 《Biologia》2013,68(1):131-141
For the first time the life cycle of the common land snail Trochulus hispidus was completely described in Central Europe (Poland). This is a semelparous species predominantly with an annual life cycle and the reproductive period lasting from April till October. The first young snails hatch in spring, grow rapidly in summer and reach ca. 4 whorls until winter. In spring of the next year they mature and reproduce. After that they die. There is hardly any growth from late autumn till early spring. The average proportional growth rate is ca. 0.3 whorl/month in the wild. The fastest growth is present in the youngest snails and then gradually decreases over the course of their age. Laboratory and field observations allowed for establishing the following life cycle parameters: eggs calcified, almost spherical, ca. 1.5 mm, laid in spring and summer in batches of between 1 and 47. Time to hatching is 6–24 days, hatching is asynchronous; newly-hatched snails have approximately 1.5 whorls. Analysis of food preferences revealed, that T. hispidus tends to restrict its diet during the life. Generally the youngest snails equally consumed leaves of all four tree species offered (Fraxinus excelsior, Acer pseudoplatanus, Tilia cordata and A. platanoides) whereas adults preferred F. excelsior over A. pseudoplatanus and A. platanoides. 相似文献
110.
Primož Treven Kristyna Turkova Aljoša Trmčić Tanja Obermajer Irena Rogelj Bojana Bogovič Matijašić 《Folia microbiologica》2013,58(6):623-630
Lactobacillus gasseri K7 is a probiotic strain that produces bacteriocins gassericin K7 A and K7 B. In order to develop a real-time quantitative PCR assay for the detection of L. gasseri K7, 18 reference strains of the Lactobacillus acidophilus group and 45 faecal samples of adults who have never consumed strain K7 were tested with PCR using 14 pairs of primers specific for gassericin K7 A and K7 B gene determinants. Incomplete gassericin K7 A or K7 B gene clusters were found to be dispersed in different lactobacilli strains as well as in faecal microbiota. One pair of primers was found to be specific for the total gene cluster of gassericin K7A and one for gassericin K7B. The real-time PCR analysis of faecal samples spiked with K7 strain revealed that primers specific for the gene cluster of the gassericin K7 A were more suitable for quantitative determination than those for gassericin K7 B, due to the lower detection level. Targeting of the gassericin K7 A or K7 B gene cluster with specific primers could be used for detection and quantification of L. gasseri K7 in human faecal samples without prior cultivation. The results of this study also present new insights into the prevalence of bacteriocin-encoding genes in gastrointestinal tract. 相似文献