全文获取类型
收费全文 | 433篇 |
免费 | 24篇 |
国内免费 | 2篇 |
出版年
2023年 | 7篇 |
2022年 | 8篇 |
2021年 | 14篇 |
2020年 | 13篇 |
2019年 | 10篇 |
2018年 | 18篇 |
2017年 | 10篇 |
2016年 | 14篇 |
2015年 | 8篇 |
2014年 | 16篇 |
2013年 | 40篇 |
2012年 | 36篇 |
2011年 | 33篇 |
2010年 | 17篇 |
2009年 | 19篇 |
2008年 | 34篇 |
2007年 | 23篇 |
2006年 | 23篇 |
2005年 | 15篇 |
2004年 | 16篇 |
2003年 | 19篇 |
2002年 | 14篇 |
2001年 | 3篇 |
2000年 | 6篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 6篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 5篇 |
1984年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有459条查询结果,搜索用时 46 毫秒
451.
Improved yield,fruit quality,and salt resistance in tomato co-overexpressing LeNHX2 and SlSOS2 genes
Mostapha Maach María Pilar Rodríguez-Rosales Kees Venema Mustapha Akodad Abdelmajid Moumen Ali Skalli Mourad Baghour 《Physiology and Molecular Biology of Plants》2021,27(4):703
The K+, Na+/H+ antiporter LeNHX2 and the regulatory kinase SlSOS2 are important determinants of salt tolerance in tomato plants and their fruit production ability. In this work, we have analyzed the effects of LeNHX2 and SlSOS2 co-overexpression on fruit production, quality in tomato plants (Solanum lycopersicum L. cv. MicroTom), and analyzed physiological parameters related to salt tolerance. Plants overexpressing LeNHX2, SlSOS2 or both were grown in greenhouse. They were treated with 125 mM NaCl or left untreated and their salt tolerance was analyzed in terms of plant biomass and fruit yield. Under NaCl cultivation conditions, transgenic tomato plants overexpressing either SlSOS2 or LeNHX2 or both grew better and showed a higher biomass compared to their wild-type plants. Proline, glucose and protein content in leaves as well as pH and total soluble solid (TSS) in fruits were analyzed. Our results indicate that salinity tolerance of transgenic lines is associated with an increased proline, glucose and protein content in leaves of plants grown either with or without NaCl. Salt treatment significantly reduced yield, pH and TSS in fruits of WT plants but increased yield, pH and TSS in fruits of transgenic plants, especially those overexpressing both LeNHX2 and SlSOS2. All these results indicate that the co-overexpression of LeNHX2 and SlSOS2 improve yield and fruit quality of tomato grown under saline conditions. 相似文献
452.
M Ahsaini F Tazi S Mellas J Elammari A Khalouk R Stuurman-Wieringa MJ Elfassi MH Farih H Elfatmi A Amarti 《Journal of medical case reports》2012,6(1):269
ABSTRACT: INTRODUCTION: Testicular cancer is the most common malignancy in men 15- to 35-years-old. The North American standard classification divides testicular cancers into germ cell tumors and non-germ cell tumors. The lymphatic spread of germ cell tumors usually involves the retroperitoneal lymph nodes. However, this spread to the retroperitoneum rarely involves the hepatic hilum. We describe an unusual case of metastatic choriocarcinoma of the testis that was clinically mimicked by a cholestatic jaundice. This is an unusual presentation of testicular cancer and, to the best of our knowledge, the first report of this kind in the literature. CASE PRESENTATION: A 28-year-old Moroccan man presented with a four-week history of progressive obstructive jaundice, and weight loss to our emergency department. Abdominal ultrasound showed a dilatation of the biliary ducts due to pathologically enlarged lymph nodes of the hepatic hilum. A complete clinical and radiologic assessment to discover the primary tumor was negative except for pulmonary metastasis. In the laboratory findings at admission there were signs of cholestasis with an abnormal increase in the rate of testicular tumor markers (serum beta-human chorionic gonadotropin level was 11,000IU/ml), which subsequently led to the suspicion of a testicular tumor. Further evaluation included testicular palpation and ultrasound which revealed a testicular nodule. The patient underwent an inguinal orchidectomy of the right testis and histopathological examination confirmed a pure choriocarcinoma. The prognosis was poor due to lymph node involvement at the hepatic hilum. He died one month later, despite general chemotherapy. CONCLUSIONS: The clinical presentation of the disease and the rarity of this entity are two remarkable characteristics described in this case report which are rarely reported in literature. 相似文献
453.
Quantitative and qualitative analyses based on planktonic foraminifera of two sections (Oued Derdoussa and Djebel Meni) from lower Chelif basin (northern Algeria) enable us to identify for the first time a sequence of bioevents calibrated with the geomagnetic polarity time scale. The identified bioevents of late Miocene formations are useful for a high-resolution correlation in the whole western Mediterranean at local and regional scales. In particular, this work reveals that the sequence covers an interval of time that extends from the upper Tortonian up to the pre-evaporite Messinian period. Indeed, the base of the succession starts with a change in the coiling direction (from dextral to sinistral) of Neogloboquadrina acostaensis as the first bioevent. This later corresponds to the bioevent (1–8) assigned to the Tortonian sediments. This period is marked by the presence of Globorotalia menardii in sinistral coiled form that was substituted gradually with dextral coiled. The Tortonian/Messinian (T/M) boundary coincides to some extent with a sharp replacement of G. menardii group (I and II) with the first common occurrence (FCO) of Globorotalia miotumida plexus few meters below the development of the Tripoli diatomite formation (bioevent 9). This later is dominated mainly by highly convex species (G. miotumida plexus) marked by the presence of Globorotalia mediterranea in contrast with the marly formation at the base of the section. In this part, the recorded bioevents (10 to 17) are assigned to the Messinian sediments. Thus, the Tripoli formation shows the influx of Globorotalia nicolae and a small incursion of the dextrally coiled of Globorotalia scitula at the top of Oued Derdoussa section as a local bioevent that may be related to the local palaeoenvironment. We notice the absence of the change in the coiling from sinistral to dextral of N. acostaensis during the upper Messinian, this may be due to the coincidence of this bioevent with the barren levels. 相似文献
454.
Cellular extracts ofEscherichia coli severely impair the protein-phosphorylating activity in vitro of animal enzymes of both the casein-kinase type and the histone-kinase type. This blockade is due to a protein, probably dimeric, acting as a noncompetitive inhibitor, which has been purified to near-homogeneity from the soluble fraction of bacterial cells by chromatographic procedures. 相似文献
455.
Essentially employed for the treatment of airway obstructions in humans, β-agonists are also known to have an anabolic effect in animals’ skeletal muscle. In vivo and in vitro studies have attested the increase in animal body mass and the hypertrophy of muscle cells following the administration of specific β-agonists. However, the contribution of β-agonists to C2C12 myoblasts growth remains obscure. We therefore aimed to investigate the impact of β1-and β2-agonist drugs on the proliferation and differentiation of skeletal muscle cells. Direct observations and cytotoxicity assay showed that clenbuterol, salbutamol, cimaterol and ractopamine enhanced muscle cell growth and viability during the proliferation stage. Structural examinations coupled to Western blot analysis indicated that salbutamol and cimaterol triggered a decrease in myotube formation. A better comprehension of the effect of β-agonists on myogenic regulatory genes in the muscle cells is crucial to establish a specific role of β-agonists in muscle development, growth, and regeneration. 相似文献
456.
457.
458.
Mohammed Haruna Jaiswal Sanjay K. Mohammed Mustapha Mbah Glory C. Dakora Felix D. 《Physiology and Molecular Biology of Plants》2020,26(6):1263-1280
Physiology and Molecular Biology of Plants - With legumes, symbiotic N2 fixation can meet the species N demand and reduce the over-reliance on chemical fertilizers in tropical regions where N... 相似文献
459.
Mustapha Amyere Virginie Aerts Pascal Brouillard Brendan?A.S. McIntyre Fran?ois?P. Duhoux Michel Wassef Odile Enjolras John?B. Mulliken Olivier Devuyst Hélène Antoine-Poirel Laurence?M. Boon Miikka Vikkula 《American journal of human genetics》2013,92(2):188-196
Inherited vascular malformations are commonly autosomal dominantly inherited with high, but incomplete, penetrance; they often present as multiple lesions. We hypothesized that Knudson’s two-hit model could explain this multifocality and partial penetrance. We performed a systematic analysis of inherited glomuvenous malformations (GVMs) by using multiple approaches, including a sensitive allele-specific pairwise SNP-chip method. Overall, we identified 16 somatic mutations, most of which were not intragenic but were cases of acquired uniparental isodisomy (aUPID) involving chromosome 1p. The breakpoint of each aUPID is located in an A- and T-rich, high-DNA-flexibility region (1p13.1–1p12). This region corresponds to a possible new fragile site. Occurrences of these mutations render the inherited glomulin variant in 1p22.1 homozygous in the affected tissues without loss of genetic material. This finding demonstrates that a double hit is needed to trigger formation of a GVM. It also suggests that somatic UPID, only detectable by sensitive pairwise analysis in heterogeneous tissues, might be a common phenomenon in human cells. Thus, aUPID might play a role in the pathogenesis of various nonmalignant disorders and might explain local impaired function and/or clinical variability. Furthermore, these data suggest that pairwise analysis of blood and tissue, even on heterogeneous tissue, can be used for localizing double-hit mutations in disease-causing genes. 相似文献