全文获取类型
收费全文 | 20185篇 |
免费 | 1154篇 |
国内免费 | 151篇 |
专业分类
耳鼻咽喉 | 250篇 |
儿科学 | 525篇 |
妇产科学 | 732篇 |
基础医学 | 2182篇 |
口腔科学 | 579篇 |
临床医学 | 1673篇 |
内科学 | 4009篇 |
皮肤病学 | 416篇 |
神经病学 | 943篇 |
特种医学 | 757篇 |
外国民族医学 | 11篇 |
外科学 | 3508篇 |
综合类 | 364篇 |
现状与发展 | 2篇 |
一般理论 | 11篇 |
预防医学 | 1747篇 |
眼科学 | 576篇 |
药学 | 1861篇 |
中国医学 | 139篇 |
肿瘤学 | 1205篇 |
出版年
2024年 | 17篇 |
2023年 | 267篇 |
2022年 | 801篇 |
2021年 | 1169篇 |
2020年 | 637篇 |
2019年 | 793篇 |
2018年 | 1082篇 |
2017年 | 625篇 |
2016年 | 660篇 |
2015年 | 682篇 |
2014年 | 936篇 |
2013年 | 1104篇 |
2012年 | 1597篇 |
2011年 | 1762篇 |
2010年 | 1000篇 |
2009年 | 719篇 |
2008年 | 1014篇 |
2007年 | 1028篇 |
2006年 | 938篇 |
2005年 | 901篇 |
2004年 | 780篇 |
2003年 | 713篇 |
2002年 | 644篇 |
2001年 | 151篇 |
2000年 | 125篇 |
1999年 | 105篇 |
1998年 | 86篇 |
1997年 | 80篇 |
1996年 | 76篇 |
1995年 | 72篇 |
1994年 | 64篇 |
1993年 | 56篇 |
1992年 | 64篇 |
1991年 | 66篇 |
1990年 | 66篇 |
1989年 | 55篇 |
1988年 | 56篇 |
1987年 | 47篇 |
1986年 | 40篇 |
1985年 | 41篇 |
1984年 | 45篇 |
1983年 | 38篇 |
1982年 | 37篇 |
1981年 | 25篇 |
1980年 | 23篇 |
1978年 | 19篇 |
1977年 | 17篇 |
1976年 | 19篇 |
1974年 | 16篇 |
1973年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
A 71 year-old woman with a large tumor of the upper lobe of the left lung was diagnosed as having metastatic adrenal cortical carcinoma nine years after the initial adrenalo-nephrectomy. The patient was well with no recurrence for six years following resection of the single lung metastasis. 相似文献
82.
Mohamed Chahine Paul B. Bennett Alfred L. George Jr Richard Horn 《Pflügers Archiv : European journal of physiology》1994,427(1-2):136-142
Full-length deoxyribonucleic acid, complementary (cDNA) constructs encoding the-subunit of the adult human skeletal muscle Na+ channel, hSkM1, were prepared. Functional expression was studied by electrophysiological recordings from cRNA-injectedXenopus oocytes and from transiently transfected tsA201 cells. The Na+ currents of hSkM1 had abnormally slow inactivation kinetics in oocytes, but relatively normal kinetics when expressed in the mammalian cell line. The inactivation kinetics of Na+ currents in oocytes, during a depolarization, were fitted by a weighted sum of two decaying exponentials. The time constant of the fast component was comparable to that of the single component observed in mammalian cells. The block of hSkM1 Na+ currents by the extracellular toxins tetrodotoxin (TTX) and -conotoxin (CTX) was measured. The IC50 values were 25 nM (TTX) and 1.2 M (CTX) in oocytes. The potency of TTX is similar to that observed for the rat homolog rSkM1, but the potency of CTX is 22-fold lower in hSkM1, primarily due to a higher rate of toxin dissociation in hSkM1. Single-channel recordings were obtained from outside-out patches of oocytes expressing hSkM1. The single-channel conductance, 24.9 pS, is similar to that observed for rSkM1 expressed in oocytes. 相似文献
83.
Bernard Boutevin Yves Pitrasanta Mohamed Taha 《Macromolecular chemistry and physics.》1982,183(12):2985-2993
A kinetic study of the redox telomerization of vinyl chloride with carbon tetrachloride was carried out. Transfer constants of PVC to the metallic ion (CFen), initiation rate (ki), and functionnality of the resulting telomers were measured. Instantaneous and cumulated polymerization degrees, (DPn )i and (DPn )cum were determined with the help of a theoretical study. These constants provide a rigorous control of the telomerization of vinyl chloride with RCCl3, (R containing an alcohol or ester group). 相似文献
84.
Mounir Fouad F Mamer O Khayyal M Sauriol F Lesimple A Ruhenstroth-Bauer G 《Medical hypotheses》2004,63(6):1024-1034
We are elaborating on the kinetics and mechanisms of septic rabbit liver to de novo biosynthesize acute-phase response (APR) proteins under in vitro conditions of deepening ischemia in reference to their in vivo prevalence in serum and cerebrospinal fluids (CSF) collected at predetermined times. The significance of the data is interpreted as relevant to grafting cadaveric liver into end-stage liver diseased patients and APR-induced ischemic heart diseases (IHD). Hepatic APR was induced by CCl(4)-intubation, and the administration of cholera toxin (CT) or scorpion venom (SV), or both, to rabbits. Hepatic functional efficiency, in terms of biosynthesis of APR proteins in closed circuit perfusion of the isolated intoxicated liver with oxygenated saline or L-15 media paralleled the two-dimensional immunoelectrophoresis (2D-IEP) spectrum of APR serum proteins at time of liver isolation. We are suggesting: (a) in vitro biosynthesis of plasma proteins by isolated perfused liver is the result of in vivo decoded and retained APR inflammatory signals; and (b) decoded inflammatory signals are expressed not withstanding the perfusate's organic composition. Furthermore, 90 min of ischemic perfusion in saline or L-15 medium precipitated mitochondrial aberrations which resulted in further deterioration of de novo biosynthesis of APR plasma proteins. Regardless of the nature of the inflammatory stimuli, mitochondrial aberrations rendered the perfused organ a biologically inert tissue mass that was incapable of resuming biological function upon perfusion with oxygenated L-15 medium. This is most likely due to ischemia-induced irreversible hepatic necrosis. Thus, in vitro aberrations of mitochondrial function(s) critically limit the capability of the isolated liver to resume its organic function to sustain biosynthesis of de novo plasma proteins. Extrapolation of these results to the surgical management of end-stage liver diseases points to the importance of the status and the handling protocol(s) of the cadaver donor liver prior to successful grafting. We conclude that although histology of a cadaver liver may reveal well-preserved hepatic cellular organelles with at least minimal intra- and intercellular communication required for viable hepatic function, we deem it essential to further define acceptable minimal capabilities to de novo biosynthesize plasma proteins by a cadaver liver as a measure of its functional viability and suitability for transplantation. Ultimately, this measure may improve the success of liver transplants with minimal surgical and drug interventions. 相似文献
85.
86.
Relationship between ROS production, apoptosis and DNA denaturation in spermatozoa from patients examined for infertility 总被引:24,自引:0,他引:24
Moustafa MH Sharma RK Thornton J Mascha E Abdel-Hafez MA Thomas AJ Agarwal A 《Human reproduction (Oxford, England)》2004,19(1):129-138
BACKGROUND: The aim of this study was to examine the role of apoptosis and reactive oxygen species (ROS) in inducing DNA damage in ejaculated spermatozoa. METHODS: We examined ejaculated spermatozoa from 31 patients examined for infertility and 19 healthy donors for apoptosis, production of ROS and DNA damage using annexin V binding, chemiluminescence assay and sperm chromatin structure assay. RESULTS: The percentage of spermatozoa that underwent apoptosis in the whole ejaculate and mature fraction was higher in the patients than in the donors (P<0.001 and P=0.009, respectively). Levels of ROS in the whole ejaculate and immature fraction were higher in the patients than in the donors (P=0.002 and P=0.009). Apoptosis was significantly correlated with ROS within patients in the whole ejaculate [r (95% confidence interval)=0.53 (0.19-0.86)] and in the mature [0.71 (0.39-1.00)] and immature spermatozoa [0.75 (0.45-1.00)]. Only apoptosis and the DNA fragmentation index (DFI) were significantly correlated within patients in the whole ejaculate [0.57 (0.18-0.97)]. CONCLUSIONS: DNA damage may be induced by oxidative assault. Apoptosis may not contribute significantly to the DNA damage. 相似文献
87.
Mohamed HS Ibrahim ME Miller EN Peacock CS Khalil EA Cordell HJ Howson JM El Hassan AM Bereir RE Blackwell JM 《Genes and immunity》2003,4(5):351-355
Longitudinal studies in Sudan show ethnic differences in incidence and clinical phenotypes associated with Leishmania donovani. Immunologically, bias in type 1 vs type 2 cytokine responses is important. To determine whether polymorphisms at IL4/IL9 or IFNGR1 contribute to susceptibility, we examined 59 multicase families of visceral leishmaniasis (VL) with/without post Kala-azar dermal leishmaniasis (PKDL). Multipoint nonparametric analysis (Allegro) linked IL4/IL9 to VL per se (P=0.002). Transmission disequilibrium testing with robust variance estimates confirmed association in the presence of linkage between VL per se and IL4 (P=0.008) but not IL9. Stepwise logistic regression analysis showed both IL4RP2 and IL4RP1 markers contributed significantly to the association, suggesting a common disease-associated haplotype. In contrast, IFNGR1 was linked (P=0.031) and associated (P=0.007) to PKDL but not VL or VL per se. Hence, polymorphism in a type 2 cytokine gene influences underlying susceptibility to VL, whereas IFNGR1 is specifically related to susceptibility to PKDL. 相似文献
88.
89.
Favorably tipping the balance between cytopathic and regulatory T cells to create transplantation tolerance 总被引:23,自引:0,他引:23
Therapeutic application of broadly reactive anti-T cell antibodies can lead not only to potent immunosuppression but also to profound and long-lived T cell depletion. We reasoned that a strategy that almost exclusively targets activated cytopathic donor reactive T cells and spares immunoregulatory networks might prove to be an exceptionally potent and highly selective means of producing long-term engraftment and tolerance. Herein we show that the combined administration of rapamycin and agonist IL-2- and antagonist IL-15-related cytolytic fusion proteins provides for long-term engraftment/tolerance in exceptionally stringent allotransplant models by (1) limiting the early expansion of activated T cells, (2) preserving and even exaggerating their subsequent apoptotic clearance, and (3) further amplifying the depletion of these activated T cells by antibody-dependent mechanisms, while (4) preserving CD4+CD25+ T cell-dependent immunoregulatory networks. 相似文献
90.
Triantafilou K Vakakis E Orthopoulos G Ahmed MA Schumann C Lepper PM Triantafilou M 《European journal of immunology》2005,35(8):2416-2423
Toll-like receptors (TLR) have a key role in regulating immunity against microbial agents. Engagement of TLR by bacterial, viral or fungal components leads to the production and release of inflammatory cytokines. In this study we show that mainly TLR8 and also TLR7 act as the host sensors for human parechovirus 1, a single-stranded RNA (ssRNA) virus. Furthermore, we see that the viral ssRNA genome is detected in endosomal compartments by these TLR, which activate signalling that lead to the synthesis of pro-inflammatory molecules by the host. 相似文献