首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   641篇
  免费   61篇
  国内免费   5篇
林业   2篇
农学   5篇
  2篇
综合类   127篇
农作物   22篇
水产渔业   4篇
畜牧兽医   387篇
园艺   157篇
植物保护   1篇
  2023年   19篇
  2022年   17篇
  2021年   26篇
  2020年   21篇
  2019年   40篇
  2018年   35篇
  2017年   39篇
  2016年   39篇
  2015年   44篇
  2014年   46篇
  2013年   43篇
  2012年   29篇
  2011年   38篇
  2010年   21篇
  2009年   21篇
  2008年   23篇
  2007年   24篇
  2006年   18篇
  2005年   18篇
  2004年   19篇
  2003年   10篇
  2002年   25篇
  2001年   17篇
  2000年   14篇
  1999年   8篇
  1998年   8篇
  1997年   3篇
  1996年   9篇
  1995年   4篇
  1994年   2篇
  1993年   6篇
  1992年   4篇
  1991年   2篇
  1990年   2篇
  1989年   3篇
  1988年   3篇
  1986年   1篇
  1982年   2篇
  1981年   1篇
  1980年   1篇
  1979年   1篇
  1973年   1篇
排序方式: 共有707条查询结果,搜索用时 15 毫秒
181.
AIM: To observe the effects of Arid2gene on cell proliferation and cell cycle by interference of endogenous Arid2 expression in hepatoma cells. METHODS: Three pairs of shRNA targeting Arid2gene were cloned into a shuttle vector to construct recombinant adenovirus plasmids. HEK293 cells were transfected with the recombinant adenovirus plasmids. After several rounds of the package and amplification, the high-titer adenoviruses AdsiArid2-1~3 were obtained. To verify the inhibitory effects of AdsiArid2 adenoviruses, Western blotting was used to detect the endogenous Arid2 protien expression in SMMC-7721 cells. Cell growth and cell cycle analysis were carried out by MTS assay and flow cytometry. RESULTS: High- titer recombinant adenovirus of siArid2 were successfully obtained, and named AdsiArid2-1~3, among which the AdsiArid2-3 had the best inhibitory effects. MTS assay showed that the absorbance values at 490 nm were increased at 72 h and 96 h after transduction compared with the mock and Adsicontrol groups. These data indicated that knockdown of Arid2 promoted the proliferation rate of SMMC-7721 cells(P<0.05). Moreover, the flow cytometry analysis revealed that the G1-phase distribution at 72 h in AdsiArid2 group was lower than that in mock group and Adsicontrol group. In contrast, the S-phase distribution in AdsiArid2 group was much higher than that in mock group and Adsicontrol group. CONCLUSION: The recombinant plasmids and recombinant adenovirus were successfully constructed. shRNA-mediated knockdown of Arid2 promotes the proliferation and the transition from G1 phase to S phase of hepatoma cells.  相似文献   
182.
183.
AIM:To investigate the potential mechanism of interleukin-17 (IL-17) promoting the viability, migration and invasion of human endometrial carcinoma cells. METHODS:The expression of IL-17 and microRNA-195-5p (miR-195-5p) in the human endometrial carcinoma and benign uterine lesion samples were detected by RT-qPCR. The expression of miR-195-5p in human endometrial carcinoma HEC-1-B cells after treatment with IL-17 at different concentrations for 48 h was detected by RT-qPCR. The viability, migration and invasion of HEC-1-B cells after treatment with IL-17 at 100 μg/L or transfection of miR-195-5p mimics were detected by MTT assay and Transwell assays. The viability, migration and invasion of HEC-1-B cells after over-expression of miR-195-5p combined with 100 μg/L IL-17 intervention were also observed. RESULTS:The expression of IL-17 was increased while the expression of miR-195-5p was decreased in the human endometrial carcinoma samples (P<0.05). The expression of miR-195-5p in the HEC-1-B cells after treatment with IL-17 at 10,100 and 300 μg/L for 48 h was significantly decreased (P<0.05). The results of MTT assay and Transwell experiments indicated that IL-17 at 100 μg/L enhanced the viability, migration and invasion of HEC-1-B cells, while over-expression of miR-195-5p resulted in the opposite effect. CONCLUSION:Over-expression of miR-195-5p inhibits the enhancing effects of IL-17 on the viability, invasion and migration of HEC-1-B cells.  相似文献   
184.
AIM: To compare the effects of B50, a mono-carbonyl analogue of curcumin, on the proliferation and apoptosis between homologous nasopharyngeal carcinoma cells CNE-2R and CNE-2 with different radioresistance.METHODS: The effects of B50 on cell viability and cell growth were detected by MTT assay and colony-forming experiment, respectively. The changes of cell cycle, apoptosis and mitochondrial membrane potential (MMP) were determined by flow cytometry.RESULTS: B50 inhibited the cell viability of CNE-2R cells in a time-and dose-dependent manner with the IC50 of (8.06±0.14) μmol/L (24 h), (2.49±0.02)μmol/L (48 h) and (1.42±0.02) μmol/L (72 h), which was more effective than that in CNE-2 cells . The inhibitory effect of B50 on CNE-2R cell growth was more effective than that on CNE-2 cells . After treated with B50 for 48 h, the proportion of CNE-2R cells in G2/M stage was increased from 7.1% to 34.9%, which was better than that of CNE-2 cells (from 12.4% to 35.7%). After treated with B50 for 24 h, the early apoptotic rate in CNE-2R cells was increased from 3.7% to 19.5%, which was better than that in CNE-2 cells (from 4.4% to 14.8%), and the MMP in CNE-2R cells was decreased by (43.17±3.11)%, which was better than that in CNE-2 cells .CONCLUSION: B50 is more effective on inhibiting the cell viability and cell growth, blocking the cell cycle at G2/M stage, inducing apoptosis and decreasing MMP in CNE-2R cells than those in CNE-2 cells, indicating that B50 may enhance the radio-sensitivity of CNE-2R cells by blocking the cell cycle and inducing apoptosis through mitochondrial pathway.  相似文献   
185.
The spread of both infectious and noninfectious diseases through wildlife populations is of increasing concern. Neoplastic diseases are rarely associated with population-level impacts in wildlife; however, impacts on individual health can be severe and might reflect deteriorating environmental conditions. An adult male free-ranging Blanding’s turtle (Emydoidea blandingii) originally captured in 2005 and deemed healthy, was recaptured in 2018 with a 1 × 1.5 cm intra-oral broad-based right mandibular mass. An excisional biopsy was performed, and histopathology revealed squamous cell carcinoma (SCC). Consensus herpesvirus PCR identified a novel herpesvirus (proposed name Emydoidea herpesvirus 2 [EBHV-2]) within the tumor. EBHV-2 shares 85% sequence homology with Terrapene herpesvirus 2 (TerHV-2), a herpesvirus linked to fibropapillomas in eastern box turtles (Terrapene carolina carolina). Virus-associated fibropapillomas have been identified in multiple marine turtle species and have had debilitating effects on their populations, but to date, virus-associated SCCs are rarely reported.  相似文献   
186.
Liver cell turnover is very slow, especially compared to intestines and stomach epithelium and hair cells. Since the liver is the main detoxifying organ in the body, it does not come as a surprise that the liver has an unmatched regenerative capacity. After 70% partial hepatectomy, the liver size returns to normal in about two weeks due to replication of differentiated hepatocytes and cholangiocytes. Despite this, liver diseases are regularly encountered in the veterinary clinic. Dogs primarily present with parenchymal pathologies such as hepatitis. The estimated frequency of canine hepatitis depends on the investigated population and accounts for 1%–2% of our university clinic referral population, and up to 12% in a general population. In chronic and severe acute liver disease, the regenerative and replicative capacity of the hepatocytes and/or cholangiocytes falls short and the liver is not restored. In this situation, proliferation of hepatic stem cells or hepatic progenitor cells (HPCs), on histology called the ductular reaction, comes into play to replace the damaged hepatocytes or cholangiocytes. For unknown reasons the ductular reaction is often too little and too late, or differentiation into fully differentiated hepatocytes or cholangiocytes is hampered. In this way, HPCs fail to fully regenerate the liver. The presence and potential of HPCs does, however, provide great prospectives for their use in regenerative strategies. This review highlights the regulation of, and the interaction between, HPCs and other liver cell types and discusses potential regenerative medicine-oriented strategies in canine hepatitis, making use of (liver) stem cells.  相似文献   
187.
Abstract: A male African pygmy hedgehog ( Atelerix albiventris ), estimated to be 3 years old, presented with exophthalmos and fixed abduction of the right eye. Radiographic examination revealed a retrobulbar tumor in the right orbital cavity. The mass was surgically resected but recurred 3 months later and the hedgehog died. There was no gross or microscopic evidence of salivary or lacrimal gland involvement of the tumor at surgery or at necropsy. The histopathologic, immunohistochemical, and ultrastructural findings were those of acinic cell carcinoma, the origin of which was unknown. This is the first known case of acinic cell carcinoma in an African hedgehog.  相似文献   
188.
189.
Reasons for performing study: The aetiology of genital squamous cell carcinoma (SCC) in horses remains unknown, but the similarity to the disease in man, for which papillomavirus infection has been shown to be a causal factor, requires to be investigated in horses. Hypothesis: One or more novel papillomaviruses cause equine genital SCC and its associated premalignant lesions. Methods: DNA was extracted from samples of equine genital SCC and performed rolling circle amplification, in order to identify closed circular DNA viral genomes within the samples. The amplified DNA was subcloned and sequenced and the DNA sequence compared to that of other papillomavirus genomes. Using PCR primers developed from these genomic DNA sequences, studies were then carried out in order to identify the frequency at which the viral DNA could be identified in equine genital cancer samples from horses in both the UK, Australia and Austria. Finally, in situ hybridisation using specific probes developed from this DNA sequence were used to confirm the presence of the viral RNA sequences in the neoplastic cells in these lesions. Results: The full length genome of a novel papillomavirus species was characterised from the equine genital SCC tissue and termed Equus caballus papillomavirus‐2 (EcPV‐2). Viral DNA and RNA was identified in the genital tumour samples, but not in the adjacent histologically normal tissue. EcPV‐2 DNA could not be identified in equine ocular or nasal carcinomas or within the scrotal skin or in most smegma samples obtained from tumour‐free horses. Sequencing of amplicons, generated from the archived equine genital tumours, identified variations within E1 and E6 on DNA and predicted protein level. Conclusions: A novel papillomavirus, EcPV‐2, is likely to play a causal role in the pathogenesis of equine genital epithelial tumours. Potential relevance: Identification of a papillomavirus causal for genital carcinomas in horses may lead to development of a vaccine that could be used to prevent this serious disease in horses. This would be analogous to man, where vaccination against oncogenic papillomavirus species is currently being used to help prevent cervical cancer.  相似文献   
190.
A 14-year-old spayed female domestic short-haired cat was presented for evaluation of a mass in the right eye. Ophthalmic examination revealed a blind right eye and presence of two distinct masses: a pink and a red-to-brown mass, the latter occupying most of the cornea and part of the conjunctiva. Exenteration was performed under general anesthesia, and the ocular tissues were processed routinely for histopathology. Upon microscopic examination, a malignant epithelial neoplasm and a benign vascular neoplasm were present in the cornea. The conjunctiva and the third eyelid were also affected. Upon immunohistochemistry, the epithelial tumor was positive for cytokeratin and negative for vimentin and the endothelial tumor was negative for cytokeratin and positive for vimentin. A diagnosis of squamous cell carcinoma (SCC) and hemangioma was made. The SCC was affecting the cornea, bulbar conjunctiva (lateral and inferior) and the base of the third eyelid, whereas the hemangioma was affecting the cornea and medial limbus. To the authors' knowledge, this is the first report of concomitant SCC and hemangioma affecting the ocular surface in a cat.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号