全文获取类型
收费全文 | 70905篇 |
免费 | 5262篇 |
国内免费 | 2482篇 |
出版年
2023年 | 1140篇 |
2022年 | 1060篇 |
2021年 | 2213篇 |
2020年 | 2349篇 |
2019年 | 3264篇 |
2018年 | 2837篇 |
2017年 | 2022篇 |
2016年 | 2011篇 |
2015年 | 2514篇 |
2014年 | 4743篇 |
2013年 | 5894篇 |
2012年 | 3653篇 |
2011年 | 4693篇 |
2010年 | 3573篇 |
2009年 | 3868篇 |
2008年 | 3942篇 |
2007年 | 3968篇 |
2006年 | 3520篇 |
2005年 | 3053篇 |
2004年 | 2704篇 |
2003年 | 2147篇 |
2002年 | 1927篇 |
2001年 | 1223篇 |
2000年 | 937篇 |
1999年 | 918篇 |
1998年 | 855篇 |
1997年 | 638篇 |
1996年 | 586篇 |
1995年 | 612篇 |
1994年 | 565篇 |
1993年 | 431篇 |
1992年 | 431篇 |
1991年 | 356篇 |
1990年 | 293篇 |
1989年 | 241篇 |
1988年 | 211篇 |
1987年 | 184篇 |
1986年 | 161篇 |
1985年 | 272篇 |
1984年 | 455篇 |
1983年 | 334篇 |
1982年 | 347篇 |
1981年 | 264篇 |
1980年 | 201篇 |
1979年 | 194篇 |
1978年 | 172篇 |
1977年 | 143篇 |
1976年 | 115篇 |
1975年 | 108篇 |
1973年 | 104篇 |
排序方式: 共有10000条查询结果,搜索用时 242 毫秒
71.
《Current biology : CB》2020,30(24):4826-4836.e7
72.
Elevated PRC1 in gastric carcinoma exerts oncogenic function and is targeted by piperlongumine in a p53‐dependent manner 下载免费PDF全文
《Journal of cellular and molecular medicine》2017,21(7):1329-1341
Gastric carcinoma is one of the most common malignancies worldwide and the second most frequent cause of cancer‐related death in China. Protein regulator of cytokinesis 1 (PRC1) is involved in cytokinesis and plays key roles in microtubule organization in eukaryotes. This study was aimed to analyse the expression and to investigate the functional role of PRC1 in gastric tumorigenesis. The expression of PRC1 was evaluated by qRT‐PCR, Western blot and immunohistochemistry. The biological function of PRC1 was determined by CCK‐8 proliferation assays, monolayer colony formation, xenografted nude mice and cell invasion assays by shRNA‐mediated knockdown in AGS and HGC27 cells. The regulation of PRC1 expression by piperlongumine was also investigated using dual‐luciferase reporter assay and ChIP‐qPCR analysis. PRC1 was up‐regulated in primary gastric cancers. Overexpression of PRC1 in gastric cancers was associated with poor disease‐specific survival and overall survival. PRC1 knockdown in AGS and HGC27 cell lines suppressed proliferation, reduced monolayer colony formation, inhibited cell invasion and migration ability and induced cell‐cycle arrest and apoptosis. Inhibition of PRC1 also suppressed tumour growth in vivo. We finally confirmed that PRC1 is a novel downstream target of piperlongumine in gastric cancer. Our findings supported the oncogenic role of PRC1 in gastric carcinogenesis. PRC1 might serve as a prognostic biomarker and potential therapeutic target for gastric carcinoma. 相似文献
73.
《Animal : an international journal of animal bioscience》2017,11(5):811-819
Angiogenin is a member of the ribonuclease A superfamily of proteins that has been implicated in stimulating angiogenesis but whether angiogenin can directly affect ovarian granulosa or theca cell function is unknown. Therefore, the objective of these studies was to determine the effect of angiogenin on proliferation and steroidogenesis of bovine granulosa and theca cells. In experiments 1 and 2, granulosa cells from small (1 to 5 mm diameter) follicles and theca cells from large (8 to 22 mm diameter) follicles were cultured to evaluate the dose-response effect of recombinant human angiogenin on steroidogenesis. At 30 and 100 ng/ml, angiogenin inhibited (P<0.05) granulosa cell progesterone production and theca cell androstenedione production but did not affect (P>0.10) granulosa cell estradiol production or theca cell progesterone production, and did not affect numbers of granulosa or theca cells. In experiments 3 and 4, granulosa and theca cells from both small and large follicles were cultured with 300 ng/ml of angiogenin to determine if size of follicle influenced responses to angiogenin. At 300 ng/ml, angiogenin increased large follicle granulosa cell proliferation but decreased small follicle granulosa cell progesterone and estradiol production and large follicle theca cell progesterone production. In experiments 5 and 6, angiogenin stimulated (P<0.05) proliferation and DNA synthesis in large follicle granulosa cells. In experiment 7, 300 ng/ml of angiogenin increased (P<0.05) CYP19A1 messenger RNA (mRNA) abundance in granulosa cells but did not affect CYP11A1 mRNA abundance in granulosa or theca cells and did not affect CYP17A1 mRNA abundance in theca cells. We conclude that angiogenin appears to target both granulosa and theca cells in cattle, but additional research is needed to further understand the mechanism of action of angiogenin in granulosa and theca cells, as well as its precise role in folliculogenesis. 相似文献
74.
Abstract SV1 was observed to have obvious synergism and could delay housefly ( Musca domestica vicina ) resistance development to Dipterex. The penetration rates of Dipterex through housefly cuticle were determined in a susceptible and two resistant strains. The results indicated that the penetration in the resistant housefly strains was obviously slower than in the susceptible one. The penetrating rate of SV1 + Dipterex (in mixture) was higher than that of Dipterex. The penetration reduction in resistant houseflies may be an important factor in bringing forth resistance. The increase of the penetrating rate of Dipterex and the decrease of its metabolic rate are regarded as the important mechanisms of SV1 synergism to Dipterex. 相似文献
75.
Arash Salmaninejad Saeed Farajzadeh Valilou Arezoo Gowhari Shabgah Saeed Aslani Malihe Alimardani Alireza Pasdar Amirhossein Sahebkar 《Journal of cellular physiology》2019,234(10):16824-16837
Over the course of past few years, cancer immunotherapy has been accompanied with promising results. However, preliminary investigations with respect to immunotherapy concentrated mostly on targeting the immune checkpoints, nowadays, emerge as the most efficient strategy to raise beneficial antitumor immune responses. Programmed cell death protein 1 (PD-1) plays an important role in subsiding immune responses and promoting self-tolerance through suppressing the activity of T cells and promoting differentiation of regulatory T cells. PD-1 is considered as an immune checkpoint and protects against autoimmune responses through both induction of apoptosis in antigen-specific T cells and inhibiting apoptosis in regulatory T cells. Several clinical trials exerting PD-1 monoclonal antibodies as well as other immune-checkpoint blockades have had prosperous outcomes and opened new horizons in tumor immunotherapy. Nonetheless, a bulk of patients have failed to respond to these newly emerging immune-based approach and the survival rate was not satisfying. Additional strategies, especially combination therapies, has been initiated and been further promising. Attempts to identify novel and well-suited predictive biomarkers are also sensed. In this review, the promotion of cancer immunotherapy targeting PD-1 immunoinhibitory pathway is discussed. 相似文献
76.
Rene Rodriguez-Gutierrez Jose Gerardo González Deven Parmar Farheen. Shaikh Pio Cruz-López 《Journal of lipid research》2022,63(7):100233
Saroglitazar, being a dual PPAR-α/γ agonist, has shown beneficial effect in diabetic dyslipidemia and hypertriglyceridemia. Fibrates are commonly used to treat severe hypertriglyceridemia. However, the effect of saroglitazar in patients with moderate to severe hypertriglyceridemia was not evaluated. We conducted a study to compare the efficacy and safety of saroglitazar (4 mg) with fenofibrate (160 mg) in patients with moderate to severe hypertriglyceridemia. This was a multicenter, randomized, double-blinded, double-dummy, active-control, and noninferiority trial in adult patients with fasting triglyceride (TG) levels of 500–1,500 mg/dl. The patients were randomized in a 1:1 ratio to receive daily dose of saroglitazar or fenofibrate for 12 weeks. The primary efficacy end point was the percent change in TG levels at week 12 relative to baseline. The study comprised of 41 patients in the saroglitazar group and 41 patients in the fenofibrate group. We found that the percent reduction from baseline in TG levels at week 12 was significantly higher in the saroglitazar group (least square mean = ?55.3%; SE = 4.9) compared with the fenofibrate group (least square mean = ?41.1%; SE = 4.9; P = 0.048). Overall, 37 treatment-emergent adverse events (AEs) were reported in 24 patients (saroglitazar: 13; fenofibrate: 11). No serious AEs were reported, and no patient discontinued the study because of AEs. We conclude that saroglitazar (4 mg) is noninferior to fenofibrate (160 mg) in reducing TG levels after 12 weeks of treatment, was safe, and well tolerated. 相似文献
77.
Jie Zhang Wei Hong Liang Guo Yifen Wang Yi Wang 《Biotechnology and bioengineering》2020,117(9):2911-2917
Clostridium tyrobutyricum ATCC 25755 is known as a natural hyper-butyrate producer with great potentials as an excellent platform to be engineered for valuable biochemical production from renewable resources. However, limited transformation efficiency and the lack of genetic manipulation tools have hampered the broader applications of this micro-organism. In this study, the effects of Type I restriction-modification system and native plasmid on conjugation efficiency of C. tyrobutyricum were investigated through gene deletion. The deletion of Type I restriction endonuclease resulted in a 3.7-fold increase in conjugation efficiency, while the additional elimination of the native plasmid further enhanced conjugation efficiency to 6.05 ± 0.75 × 103 CFU/ml-donor, which was 15.3-fold higher than the wild-type strain. Fermentation results indicated that the deletion of those two genetic elements did not significantly influence the end-products production in the resultant mutant ΔRMIΔNP. Thanks to the increased conjugation efficiency, the CRISPR-Cas9/Cpf1 systems, which previously could not be implemented in C. tyrobutyricum, were successfully employed for genome editing in ΔRMIΔNP with an efficiency of 12.5–25%. Altogether, approaches we developed herein offer valuable guidance for establishing efficient DNA transformation methods in nonmodel micro-organisms. The ΔRMIΔNP mutant can serve as a great chassis to be engineered for diverse valuable biofuel and biochemical production. 相似文献
78.
79.
《Bioorganic & medicinal chemistry》2020,28(22):115746
Human T cell lymphotropic virus type 1 (HTLV-1) is a human retrovirus that infects approximately 10–20 million people worldwide and causes an aggressive neoplasia (adult T-cell leukemia/lymphoma - ATL). Therapeutic approaches for the treatment of ATL have variable effectiveness and poor prognosis, thus requiring strategies to identify novel compounds with activity on infected cells. In this sense, we initially screened a small series of 25 1,2,3-triazole derivatives to discover cell proliferation inhibitors and apoptosis inducers in HTLV-1-infected T-cell line (MT-2) for further assessment of their effect on viral tax activity through inducible-tax reporter cell line (Jurkat LTR-GFP). Eight promising compounds (02, 05, 06, 13, 15, 21, 22 and 25) with activity ≥70% were initially selected, based on a suitable cell-based assay using resazurin reduction method, and evaluated towards cell cycle, apoptosis and Tax/GFP expression analyses through flow cytometry. Compound 02 induced S phase cell cycle arrest and compounds 05, 06, 22 and 25 promoted apoptosis. Remarkably, compounds 22 and 25 also reduced GFP expression in an inducible-tax reporter cell, which suggests an effect on Tax viral protein. More importantly, compounds 02, 22 and 25 were not cytotoxic in human hepatoma cell line (Huh-7). Therefore, the discovery of 3 active and non-cytotoxic compounds against HTLV-1-infected cells can potentially contribute, as an initial promising strategy, to the development process of new drugs against ATL. 相似文献
80.