全文获取类型
收费全文 | 1408篇 |
免费 | 75篇 |
国内免费 | 1篇 |
出版年
2023年 | 36篇 |
2022年 | 18篇 |
2021年 | 31篇 |
2020年 | 32篇 |
2019年 | 26篇 |
2018年 | 49篇 |
2017年 | 59篇 |
2016年 | 67篇 |
2015年 | 54篇 |
2014年 | 95篇 |
2013年 | 117篇 |
2012年 | 112篇 |
2011年 | 111篇 |
2010年 | 85篇 |
2009年 | 62篇 |
2008年 | 83篇 |
2007年 | 53篇 |
2006年 | 71篇 |
2005年 | 67篇 |
2004年 | 67篇 |
2003年 | 69篇 |
2002年 | 44篇 |
2001年 | 8篇 |
2000年 | 6篇 |
1999年 | 3篇 |
1998年 | 9篇 |
1997年 | 8篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1994年 | 6篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1972年 | 3篇 |
1969年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
1964年 | 1篇 |
1950年 | 1篇 |
1947年 | 1篇 |
排序方式: 共有1484条查询结果,搜索用时 15 毫秒
1.
Medine Gulluce Tugba Bal Hakan Ozkan Ahmet Adiguzel Fikrettin Sahin Derya Yanmis 《Geomicrobiology journal》2014,31(5):445-451
In this study, the bacteria having ore enrichment potential were isolated from three different magnesite quarries located in Erzurum-Askale borderlines. The obtained isolates were identified and characterized according to the conventional (morphological, physiological and biochemical tests) and molecular techniques (fatty acid methyl ester profiles (FAME), BOX PCR and 16S rDNA). According to sequence analysis, they were determined as Exiguobacterium aurantiacum (4), Exiguobacterium sibiricum (2), Bacillus sp. (2), Staphylococcus epidermidis (2), Staphylococcus haemolyticus (1), Shewanella baltica (1) and Klebsiella oxytoca (1), respectively. 相似文献
2.
Teoman Kankılıç Perinçek Seçkinozan Şeker Tolga Kankılıç Kubilay Toyran Jan Zima 《Zoology in the Middle East.》2017,63(3):181-188
A new karyotype for blind mole rats was recorded in Tunceli province in Eastern Turkey. The karyotype contained 44 chromosomes, including 13 biarmed pairs, 7 acrocentric pairs, and one heteromorphic pair with a submetacentric and an acrocentric homologue in the autosomal complement (FNa=69). The X chromosome was submetacentric and the Y chromosome medium-sized subtelocentric (FN=73). Distinct dark centromeric C-bands were observed on most of the biarmed and three pairs of the acrocentric autosomes. The NORs were detected on short arms of three subtelocentric pairs and one acrocentric pair of autosomes. The diploid number of chromosomes and the karyotype characteristics observed are obviously unique among hitherto studied populations of blind mole rats and the complement can be evaluated as a new chromosome race of Nannospalax xanthodon. The distribution ranges of individual chromosome races of the species recorded in Eastern Anatolia are revised and possible interracial hybridization is discussed in respect of the finding of a new race. 相似文献
3.
The accumulation of heavy metals in Typha latifolia L. grown in a stream carrying secondary effluent
Typha latifolia L. from aquatic plants is widely found throughout Kehli Stream (Elazig, Turkey). This study examined the uptake of some metals by T. latifolia and the transfer from roots to other plant parts. The accumulation of Mn in T. latifolia L. can be suggested as a tolerance strategy due to its transfer factor higher than 1.0. The enrichment coefficients in the leaves of T. latifolia L. were higher than 1.0 for Zn and Mn and often lower than 1.0 for other metals. Similarly, the enrichment coefficients of all metals, except for Cr, in roots of T. latifolia L. were higher than 1.0. This study demonstrated that T. latifolia L. could be considered as either a bio-indicator or a bio-accumulator for sediments and water polluted by metals. 相似文献
4.
Allopatric isolation in glacial refugia has caused differentiation and speciation in many taxa globally. In this study, we investigated the nuclear and mitochondrial genetic differentiation of the long fingered bat, Myotis capaccinii during the ice ages in south-eastern Europe and Anatolia. The mitochondrial DNA (mtDNA) analyses indicated a suture zone similar to those recorded in other animal species, including bats, suggesting the association of more than one refugium with the region. Contrary to most of the other species where a suture zone was seen in Anatolia, for M. capaccinii the geographical location of the genetic break was in south-eastern Europe. This mitochondrial differentiation was not reflected in the nuclear microsatellites, however, suggesting that the lack of contact during the ice ages did not result in reproductive isolation. Hence taxonomically, the two mitochondrial clades cannot be treated as separate species. 相似文献
5.
Altinoz Meric A. Topcu Gulacti Hacimuftuoglu Ahmet Ozpinar Alp Ozpinar Aysel Hacker Emily Elmaci İlhan 《Neurochemical research》2019,44(8):1796-1806
Neurochemical Research - Noscapine is a phthalide isoquinoline alkaloid that easily traverses the blood brain barrier and has been used for years as an antitussive agent with high safety. Despite... 相似文献
6.
7.
Zeynep Kurkcuoglu Ahmet Bakan Duygu Kocaman Ivet Bahar Pemra Doruker 《PLoS computational biology》2012,8(9)
Catalytic loop motions facilitate substrate recognition and binding in many enzymes. While these motions appear to be highly flexible, their functional significance suggests that structure-encoded preferences may play a role in selecting particular mechanisms of motions. We performed an extensive study on a set of enzymes to assess whether the collective/global dynamics, as predicted by elastic network models (ENMs), facilitates or even defines the local motions undergone by functional loops. Our dataset includes a total of 117 crystal structures for ten enzymes of different sizes and oligomerization states. Each enzyme contains a specific functional/catalytic loop (10–21 residues long) that closes over the active site during catalysis. Principal component analysis (PCA) of the available crystal structures (including apo and ligand-bound forms) for each enzyme revealed the dominant conformational changes taking place in these loops upon substrate binding. These experimentally observed loop reconfigurations are shown to be predominantly driven by energetically favored modes of motion intrinsically accessible to the enzyme in the absence of its substrate. The analysis suggests that robust global modes cooperatively defined by the overall enzyme architecture also entail local components that assist in suitable opening/closure of the catalytic loop over the active site. 相似文献
8.
Serum paraoxonase (PON1) is a key enzyme related to high‐density lipoprotein (HDL)‐cholesterol particle. It can prevent the oxidation of low‐density lipoprotein (LDL) and HDL. The present article focuses on the in vitro inhibition role of some antiepileptic drugs (AEDs) such as valproic acid, gabapentin, primidone, phenytoin, and levetiracetam on human paraoxonase (hPON1). Therefore, PON1 was purified from human serum with a specific activity of 3976.36 EU/mg and 13.96% yield by using simple chromatographic methods. The AEDs were tested at various concentrations, which showed reduced in vitro hPON1 activity. IC50 values for gabapentin, valproic acid, primidone, phenytoin, and levetiracetam were found to be 0.35, 0.67, 0.87, 6.3, and 53.3 mM, respectively. Ki constants were 0.261 ± 0.027, 0.338 ± 0.313, 0.410 ± 0.184, 10.3 ± 0.001, and 43.01 ± 0.003 mM, respectively. Gabapentin exhibited effective inhibitory activity as compared with the other drugs. The inhibition mechanisms of all compounds were noncompetitive. 相似文献
9.
Investigation of the effect of naringenin on oxidative stress‐related alterations in testis of hydrogen peroxide‐administered rats 下载免费PDF全文
Zafer Sahin Ahmet Ozkaya Gokhan Cuce Mirac Uckun Ertan Yologlu 《Journal of biochemical and molecular toxicology》2017,31(9)
Testis tissue is prone to oxidation because its plasma membrane contains many polyunsaturated fatty acids. Naringenin is a plant‐derived natural flavonoid. We investigated the possible ameliorative role of naringenin on the hydrogen peroxide (H2O2)‐induced testicular damage in Wistar rats. Animals received 12 mg/kg H2O2 by intraperitoneal injection, and 50 mg/kg naringenin via orogastric gavage for 4 weeks. In the H2O2 group, the testis malondialdehyde level increased, while the amount of reduced glutathione, glutathione transferase activities, and the testis weight decreased. There were severe testicular damages in the H2O2 group otherwise their grade were less in the naringenin + H2O2 group. However, the serum testosterone concentrations decreased in both the H2O2 and the naringenin + H2O2 groups. The testicular zinc and calcium levels reduced in the H2O2‐treated rats. In conclusion, the administration of H2O2 caused oxidative stress in the testes and naringenin supplementation decreased the H2O2‐induced effects, except for changes in testosterone levels. 相似文献
10.
Kepenek Eda Seyma Ozcinar Evren Tuncay Erkan Akcali Kamil Can Akar Ahmet Ruchan Turan Belma 《Molecular and cellular biochemistry》2020,463(1-2):33-44
Molecular and Cellular Biochemistry - Excitation–contraction coupling in normal cardiac function is performed with well balanced and coordinated functioning but with complex dynamic... 相似文献