全文获取类型
收费全文 | 28421篇 |
免费 | 2537篇 |
国内免费 | 1683篇 |
专业分类
耳鼻咽喉 | 264篇 |
儿科学 | 302篇 |
妇产科学 | 339篇 |
基础医学 | 3504篇 |
口腔科学 | 448篇 |
临床医学 | 3725篇 |
内科学 | 4589篇 |
皮肤病学 | 223篇 |
神经病学 | 1833篇 |
特种医学 | 1100篇 |
外国民族医学 | 24篇 |
外科学 | 3051篇 |
综合类 | 3975篇 |
现状与发展 | 5篇 |
一般理论 | 16篇 |
预防医学 | 1930篇 |
眼科学 | 680篇 |
药学 | 2852篇 |
12篇 | |
中国医学 | 1282篇 |
肿瘤学 | 2487篇 |
出版年
2024年 | 79篇 |
2023年 | 375篇 |
2022年 | 962篇 |
2021年 | 1282篇 |
2020年 | 939篇 |
2019年 | 856篇 |
2018年 | 972篇 |
2017年 | 841篇 |
2016年 | 873篇 |
2015年 | 1288篇 |
2014年 | 1483篇 |
2013年 | 1331篇 |
2012年 | 2165篇 |
2011年 | 2228篇 |
2010年 | 1428篇 |
2009年 | 1157篇 |
2008年 | 1604篇 |
2007年 | 1659篇 |
2006年 | 1659篇 |
2005年 | 1538篇 |
2004年 | 1233篇 |
2003年 | 1251篇 |
2002年 | 1082篇 |
2001年 | 577篇 |
2000年 | 517篇 |
1999年 | 506篇 |
1998年 | 310篇 |
1997年 | 336篇 |
1996年 | 277篇 |
1995年 | 264篇 |
1994年 | 224篇 |
1993年 | 158篇 |
1992年 | 192篇 |
1991年 | 159篇 |
1990年 | 145篇 |
1989年 | 89篇 |
1988年 | 88篇 |
1987年 | 79篇 |
1986年 | 61篇 |
1985年 | 60篇 |
1984年 | 58篇 |
1983年 | 22篇 |
1982年 | 26篇 |
1981年 | 23篇 |
1980年 | 16篇 |
1979年 | 14篇 |
1978年 | 11篇 |
1977年 | 9篇 |
1974年 | 9篇 |
1973年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
PPARgamma knockdown by engineered transcription factors: exogenous PPARgamma2 but not PPARgamma1 reactivates adipogenesis. 总被引:9,自引:0,他引:9
Delin Ren Trevor N Collingwood Edward J Rebar Alan P Wolffe Heidi S Camp 《Genes & development》2002,16(1):27-32
To determine functional differences between the two splice variants of PPARgamma (gamma1 and gamma2), we sought to selectively repress gamma2 expression by targeting engineered zinc finger repressor proteins (ZFPs) to the gamma2-specific promoter, P2. In 3T3-L1 cells, expression of ZFP55 resulted in >50% reduction in gamma2 expression but had no effect on gamma1, whereas adipogenesis was similarly reduced by 50%. However, ZFP54 virtually abolished both gamma2 and gamma1 expression, and completely blocked adipogenesis. Overexpression of exogenous gamma2 in the ZFP54-expressing cells completely restored adipogenesis, whereas overexpression of gamma1 had no effect. This finding clearly identifies a unique role for the PPARgamma2 isoform. 相似文献
52.
Florien van Heest Ilora Finlay Renée Otter Betty Meyboom-de Jong 《The British journal of general practice》2007,57(539):494-496
This study describes a novel type of support for GPs caring for patients dying at home: the establishment and evaluation of a telephone advisory service for GPs, run by GPs with a special interest in palliative care (GPwSIs) in the Netherlands 2000-2003. A growing number of GPs called for advice, 10% during out of hours. Prognosis of the patients was generally short (days to weeks in 70% of cases). Most advice sought by GPs concerned symptom management and on evaluation, 85% of the GPs followed the advice. 相似文献
53.
Reproductive genetic counselling in non-mosaic 47,XXY patients: implications for preimplantation or prenatal diagnosis: Case report and review 总被引:3,自引:0,他引:3
Tachdjian G Frydman N Morichon-Delvallez N Dû AL Fanchin R Vekemans M Frydman R 《Human reproduction (Oxford, England)》2003,18(2):271-275
With an incidence of approximately 1 in 500 male newborns, the 47,XXY genotype is one the most common sex chromosome anomalies. It is also the most frequent genetic cause of human infertility. Some non-mosaic 47,XXY patients have sperm production which allows infertility treatment to be offered by ICSI. Therefore, the risk of transmitting a chromosome anomaly to the next generation is an important problem in reproductive genetic counselling of these patients. Here, we report on a twin pregnancy where two karyotypically normal neonates 46,XX and 46,XY were born after the use of ICSI in assisted reproduction of a patient with a non-mosaic 47,XXY syndrome. To date, only 38 evolving pregnancies including the present cases, have been reported after ICSI using sperm from non-mosaic 47,XXY patients. Although these data are scarce, they suggest that the risk of chromosome anomaly in the offspring of these patients is low; hence, their reproductive genetic counselling can be reassuring, and management of the pregnancy can proceed with caution. 相似文献
54.
Jiang S Xin R Wu X Lin S Qian Y Ren D Tang G Wang D 《American journal of medical genetics》2000,96(3):289-292
Attention deficit hyperactivity disorder (ADHD) is a prevalent disorder in children. The etiology of this disease is not clear. Genetics studies have suggested the involvement of the dopamine DRD-4 receptor gene and dopamine transporter gene (DAT1). Clinical studies have shown that monoamine oxidase-B (MAO-B) inhibitors are effective in the treatment of ADHD. These findings suggest that monoamine oxidase (MAO) genes might be involved in the origin of ADHD. In the present work, the DXS7 locus of chromosome X, which is closely linked to MAO genes, was selected as a marker to study the possible association between ADHD and MAO genes in the Chinese population. Haplotype-based haplotype relative risk (HHRR) and the transmission disequilibrium test (TDT) methods were employed to analyze the association and the linkage disequilibrium, respectively. Significant association (X(2) = 15.86; 1 df; P < 0.001) and linkage (X(2) = 14.88; 1 df; P < 0.001) were detected between the 157-bp allele of the DXS7 locus and the DSM-III-R-diagnosed ADHD (N = 72) in trios composed of father, mother, and affected offspring. The data suggested that ADHD was associated and in linkage with DXS7 locus. 相似文献
55.
While the pathological events evoked by infection are commonly described, effective host responses to bacteria and their products should primarily be protective. Heat shock protein (Hsp) expression is upregulated by many stimuli and serves to maintain intracellular protein integrity. The ability of the prototypic superantigen, Staphylococcus aureus enterotoxin B (SEB) to induce Hsps was investigated with BALB/c mice and by in vitro addition to the murine small intestinal epithelial cell line MSIE. SEB-treated (5 or 100 microg intraperitoneally) mice revealed increased Hsp25 and Hsp72, but not Hsc73, in jejunal lymphocytes and epithelial cells. A similar Hsp response to SEB occurred in MSIE cells and was preceded by activation of the ERK1/2 and p38 mitogen-activated protein kinases but not the SAPK/JNK pathway; pharmacological inhibition of ERK1/2, but not p38, significantly reduced SEB-induced Hsps. Moreover, SEB-treated MSIE cells were protected against oxidant-induced cytotoxicity (measured by 51Cr release) and F-actin depolymerization. Thus, SEB exposure results in a rapid induction of the Hsp25 and Hsp72 in intestinal epithelial cells, both directly and through lymphocyte activation, and we suggest that this event is important in protecting the gut from damage by Staphylococcus infection or in the reparatory process and may be a generalized response to lumen-derived bacterial toxins. 相似文献
56.
Shyh Ren Chiang Hung Jen Tang Ping Chin Chang Kuo Chen Cheng Wen Chien Ko Chung Hua Chen Yin Ching Chuang 《Journal of microbiology, immunology, and infection》2007,40(2):123-133
BACKGROUND AND PURPOSE: Vibrio vulnificus causes primary bacteremia and necrotizing wound infection, leading to high morbidity and mortality in humans. This study aimed to evaluate the antimicrobial effect of cefotaxime and minocycline on proinflammatory cytokine levels in a murine model of V. vulnificus infection. METHODS: We investigated the dynamics of proinflammatory cytokines and their modulation by antimicrobial agents using a murine model of V. vulnificus infection. The change in cytokine levels was followed over a time course to identify the antimicrobial activity of the drugs against V. vulnificus. BALB/c female mice were challenged with an intraperitoneal infection using a clinical invasive isolate of Vv05191, and their cytokine levels were assayed over various time points. RESULTS: Serum levels of tumor necrosis factor-alpha, interleukin (IL)-1 beta, and IL-6 post-infection were found to be inoculum dose-dependent and positively correlated to the subsequent fatality rate in the infected mice. With an inoculum of 6.6 x 10(6) colony-forming units and intraperitoneal administration of cefotaxime, minocycline, or both, the serum and peritoneal fluid cytokine levels increased and then declined gradually. Comparison of the 3 antimicrobial regimens revealed that the magnitude of reduction in cytokine levels was greatest in mice treated with cefotaxime-minocycline combination. Moreover, the peritoneal fluid cytokine level in the combination group was significantly lower than that in the groups treated with minocycline or cefotaxime alone. CONCLUSIONS: The current results support the superiority of the combination therapy in treating invasive V. vulnificus infections. 相似文献
57.
Nilius B Weidema F Prenen J Hoenderop JG Vennekens R Hoefs S Droogmans G Bindels RJ 《Pflügers Archiv : European journal of physiology》2003,445(5):584-588
The family of epithelial Ca(2+) channels (ECaC) is a unique group of highly Ca(2+)-selective channels consisting of two members, ECaC1 and ECaC2. We used carboxyl terminal truncations and mutants to delineate the molecular determinants of the Ca(2+)-dependent inhibition of ECaC. To this end, rabbit ECaC1 was expressed heterologously with green fluorescent protein (GFP) in human embryonic kidney 293 (HEK293) cells using a bicistronic vector. Deletion of the last 30 amino acids of the carboxyl terminus of ECaC1 (G701X) decreased the Ca(2+) sensitivity significantly. Another critical sequence for Ca(2+)-dependent inactivation of ECaC1 was found upstream in the carboxyl terminus. Analysis of truncations at amino acid 635, 639, 646, 649 and 653 disclosed a critical sequence involved in Ca(2+)-dependent inactivation at positions 650-653. C653X showed decreased Ca(2+) sensitivity, comparable to G701X, while E649X lacked Ca(2+)-dependent inactivation. Interestingly, the number of green fluorescent cells, which is an index of the number of transfected cells, was significantly smaller for cells transfected with truncations shorter than E649 than for cells transfected with wild-type ECaC. However, the expression level of GFP was restored in the presence of the ECaC blocker ruthenium red, suggesting that these truncations resulted in deleterious Ca(2+) influx. In conclusion, we have identified two domains in the carboxyl terminus of ECaC1 that control Ca(2+)-dependent inactivation. 相似文献
58.
Nolte MA Arens R van Os R van Oosterwijk M Hooibrink B van Lier RA van Oers MH 《Nature immunology》2005,6(4):412-418
The differentiation of hematopoietic stem cells into mature blood cell lineages is tightly regulated. Here we report that CD27, which is expressed on stem and early progenitor cells in bone marrow, can be important in this process. Deletion of CD27 increased the myeloid colony-forming potential of stem and early progenitor cells and enhanced B lymphoid reconstitutive capacity in competitive transplantation experiments. Conversely, stimulation of CD27(+) progenitor cells with CD70, the unique ligand for CD27, inhibited colony-forming potential in vitro and lymphocyte outgrowth in vivo. As CD70 is expressed only on activated immune cells, we suggest that CD27 triggering on early progenitor cells provides a negative feedback signal to leukocyte differentiation during immune activation. 相似文献
59.
氧分压在体监测仪的研制 总被引:2,自引:0,他引:2
作者报道一种稳定性较高的氧分压在体监测,为医学研究、临床诊断提供一种新的可靠的测试方法及设备,具有较大的应用价值。 相似文献
60.
我们已经在减毒鼠伤寒沙门菌SL3261以融合蛋白的形式表达了人工合成的恶性疟原虫杂合113肽基因AB(GZ-AB)。活菌以2×109CFU经口服免疫新西兰家兔,用ELISA测定抗体水平,结果于首次免疫或加强免疫后都可检测到一定水平的特异性抗体。所免疫的家免可以诱发针对恶性疟原虫抗原及GZ-AB的迟发性超敏反应(DTH)。我们的研究表明,含有多个恶性疟原虫抗原表位的人工合成基因可以在减毒鼠伤寒沙门菌中表达,活菌可诱发家兔产生特异的体液免疫及细胞免疫,为恶性疟口服活菌苗的制备打下基础。 相似文献