全文获取类型
收费全文 | 366952篇 |
免费 | 10024篇 |
国内免费 | 579篇 |
专业分类
耳鼻咽喉 | 3871篇 |
儿科学 | 12636篇 |
妇产科学 | 7968篇 |
基础医学 | 42638篇 |
口腔科学 | 8073篇 |
临床医学 | 25208篇 |
内科学 | 75366篇 |
皮肤病学 | 6768篇 |
神经病学 | 32072篇 |
特种医学 | 13241篇 |
外国民族医学 | 31篇 |
外科学 | 53867篇 |
综合类 | 3312篇 |
一般理论 | 51篇 |
预防医学 | 36958篇 |
眼科学 | 6689篇 |
药学 | 22761篇 |
中国医学 | 1259篇 |
肿瘤学 | 24786篇 |
出版年
2023年 | 1102篇 |
2022年 | 2014篇 |
2021年 | 4678篇 |
2020年 | 2484篇 |
2019年 | 4408篇 |
2018年 | 27095篇 |
2017年 | 20490篇 |
2016年 | 22769篇 |
2015年 | 5114篇 |
2014年 | 6497篇 |
2013年 | 8894篇 |
2012年 | 19124篇 |
2011年 | 33204篇 |
2010年 | 25430篇 |
2009年 | 17307篇 |
2008年 | 29379篇 |
2007年 | 32025篇 |
2006年 | 11197篇 |
2005年 | 12733篇 |
2004年 | 13058篇 |
2003年 | 13248篇 |
2002年 | 10940篇 |
2001年 | 5685篇 |
2000年 | 5940篇 |
1999年 | 4886篇 |
1998年 | 1688篇 |
1997年 | 1282篇 |
1996年 | 1101篇 |
1995年 | 1000篇 |
1994年 | 839篇 |
1993年 | 716篇 |
1992年 | 2390篇 |
1991年 | 2313篇 |
1990年 | 2175篇 |
1989年 | 1872篇 |
1988年 | 1703篇 |
1987年 | 1660篇 |
1986年 | 1537篇 |
1985年 | 1493篇 |
1984年 | 1113篇 |
1983年 | 969篇 |
1979年 | 1039篇 |
1978年 | 713篇 |
1975年 | 706篇 |
1974年 | 929篇 |
1973年 | 882篇 |
1972年 | 764篇 |
1971年 | 703篇 |
1970年 | 777篇 |
1969年 | 736篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
31.
C R Plata-Salamán 《Brain research bulletin》1991,27(5):737-738
Intracerebroventricular (ICV) microinfusion of recombinant human interleukin-1 beta (rhIL-1 beta, 0.125 to 2.0 ng/rat) dose-dependently suppressed 2 h and nighttime food intake in rats. The following daytime food intake did not change or increased. ICV infusion of bovine serum albumin (BSA), or heat-treated rhIL-1 beta had no effect on food intake. Pretreatment with dexamethasone (200 micrograms/rat, intraperitoneal) blocked the food intake suppression induced by low doses of rhIL-1 beta. This ability of dexamethasone, a synthetic corticosteroid, may have potential therapeutic implications in acute and chronic pathological processes associated with increased levels of IL-1 and appetite suppression. 相似文献
32.
Galanin-like immunoreactivity has been visualized in nerve fibers in the islets of Langerhans, suggesting an involvement of
galanin in the neural regulation of islet function. In this study, we investigated the effects of galanin on basal and stimulated
insulin and glucagon secretion by infusing the peptide at three different dose rates in rats. We also studied the direct effect
of galanin on insulin secretion from freshly isolated rat islets. At 320 pmol/kg/min, but not at 20 or 80 pmol/kg/min, galanin
lowered basal plasma insulin levels. In contrast, basal plasma glucagon levels were lowered by galanin already at 20 and 80
pmol/kg/min. Furthermore, galanin inhibited both glucose- and arginine-induced insulin release at all three dose levels, whereas
arginine-induced glucagon release was not affected by galanin. Glucose-stimulated insulin secretion from isolated rat islets
was dose-dependently suppressed by galanin (10-6-10-8M). Therefore, it is concluded that galanin in rats inhibits insulin secretion, both in vivo and in vitro, and that at lower
dose levels, the peptide also inhibits basal glucagon release. 相似文献
33.
34.
E Maquarre C Artus Z Gadhoum C Jasmin F Smadja-Joffe J Robert-Lézénès 《Leukemia》2005,19(12):2296-2303
We have recently reported that ligation of the CD44 cell surface antigen with A3D8 monoclonal antibody (mAb) triggers incomplete differentiation and apoptosis of the acute promyelocytic leukemia (APL)-derived NB4 cells. The present study characterizes the mechanisms underlying the apoptotic effect of A3D8 in NB4 cells. We show that A3D8 induces activation of both initiator caspase-8 and -9 and effector caspase-3 and -7 but only inhibition of caspase-3/7 and caspase-8 reduces A3D8-induced apoptosis. Moreover, A3D8 induces mitochondrial alterations (decrease in mitochondrial membrane potential DeltaPsi m and cytochrome c release), which are reduced by caspase-8 inhibitor, suggesting that caspase-8 is primarily involved in A3D8-induced apoptosis of NB4 cells. However, the apoptotic process is independent of TNF-family death receptor signalling. Interestingly, the general serine protease inhibitor 4-(2-aminoethyl)-benzenesulfonyl fluoride (AEBSF) decreases A3D8-induced apoptosis and when combined with general caspase inhibitor displays an additive effect resulting in complete prevention of apoptosis. These results suggest that both caspase-dependent and serine protease-dependent pathways contribute to A3D8-induced apoptosis. Finally, A3D8 induces apoptosis in all-trans-retinoic acid-resistant NB4-derived cells and in APL primary blasts, characterizing the A3D8 anti-CD44 mAb as a novel class of apoptosis-inducing agent in APL. 相似文献
35.
36.
M Lodén 《Acta pharmacologica et toxicologica》1986,58(5):382-389
The permeability of human skin to benzene, ethylene glycol, formaldehyde, and n-hexane was studied using excised skin in a flow-through diffusion cell. The rate of resorption was determined by measuring the amount of substance found in the receptor fluid beneath the skin at steady-state. The rates of resorption (microgram X cm-2 X hr-1) were: benzene 99. ethylene glycol 118, formaldehyde from a concentrated solution of formalin 319, formaldehyde from a solution of 10% formalin in phosphate buffer 16.7, and n-hexane 0.83. The amount of substance in the skin at steady-state and after 0.5 hr of exposure was also determined. For all substances, the sum of the amount in the receptor medium and in the skin at steady-state, were larger than the amount obtained by multiplying the resorption rate by the time of exposure. For benzene, ethylene glycol and n-hexane the amount absorbed during the first half-hour of exposure was considerable larger than the amount resorbed during a same unit of time at steady-state. These data call attention to the fact that the absorption rate is higher before steady state is attained. 相似文献
37.
Immunoregulators in the nervous system 总被引:15,自引:0,他引:15
C R Plata-Salamán 《Neuroscience and biobehavioral reviews》1991,15(2):185-215
The nervous system, through the production of neuroregulators (neurotransmitters, neuromodulators and neuropeptides) can regulate specific immune system functions, while the immune system, through the production of immunoregulators (immunomodulators and immunopeptides) can regulate specific nervous system functions. This indicates a reciprocal communication between the nervous and immune systems. The presence of immunoregulators in the brain and cerebrospinal fluid is the result of local synthesis--by intrinsic and blood-derived macrophages, activated T-lymphocytes that cross the blood-brain barrier, endothelial cells of the cerebrovasculature, microglia, astrocytes, and neuronal components--and/or uptake from the peripheral blood through the blood-brain barrier (in specific cases) and circumventricular organs. Acute and chronic pathological processes (infection, inflammation, immunological reactions, malignancy, necrosis) stimulate the synthesis and release of immunoregulators in various cell systems. These immunoregulators have pivotal roles in the coordination of the host defense mechanisms and repair, and induce a series of immunological, endocrinological, metabolical and neurological responses. This review summarizes studies concerning immunoregulators--such as interleukins, tumor necrosis factor, interferons, transforming growth factors, thymic peptides, tuftsin, platelet activating factor, neuro-immunoregulators--in the nervous system. It also describes the monitoring of immunoregulators by the central nervous system (CNS) as part of the regulatory factors that induce neurological manifestations (e.g., fever, somnolence, appetite suppression, neuroendocrine alterations) frequently accompanying acute and chronic pathological processes. 相似文献
38.
39.
J. Bryan Page 《Journal of urban health》2005,82(3):iii35-iii43
Contemporary discourse contains numerous examples of use of the concept of culture by social and behavioral scientists. Simple reification, where the speaker makes culture into a thing capable of action exemplifies one usage in public discourse. Some quantitative social scientists attempt to characterize people’s cultural identities by means of a single categorical variable, which often “lumps” people into categories such as “Hispanic” or “Black” that in fact have numerous culturally bounded subcategories. Approaches that emphasize cultural process are preferable to those who attempt to categorize; more complex measures of acculturation help investigators to make convincing analyses of circumstances in which health disparities occur. Examples in which investigators make appropriate use of cultural characterizations demonstrate their utility in investigating health disparities in Haitian American women, injecting and noninjecting drug users, Hispanic youth, and adult Hispanics at risk of HIV infection. Focus on culture in the study of health disparities can identify entanglements between structural factors such as poverty and lack of education and cultural factors such as beliefs about health. Qualitative methods coupled with quantitative methods have great potential to improve investigators’ grasp of cultural nuance while capturing the distribution of qualitatively derived behaviors. 相似文献