全文获取类型
收费全文 | 49227篇 |
免费 | 3599篇 |
国内免费 | 2475篇 |
专业分类
耳鼻咽喉 | 256篇 |
儿科学 | 1362篇 |
妇产科学 | 474篇 |
基础医学 | 11345篇 |
口腔科学 | 396篇 |
临床医学 | 3696篇 |
内科学 | 13615篇 |
皮肤病学 | 580篇 |
神经病学 | 1227篇 |
特种医学 | 626篇 |
外国民族医学 | 7篇 |
外科学 | 2117篇 |
综合类 | 6330篇 |
现状与发展 | 18篇 |
预防医学 | 7399篇 |
眼科学 | 388篇 |
药学 | 2526篇 |
13篇 | |
中国医学 | 862篇 |
肿瘤学 | 2064篇 |
出版年
2024年 | 47篇 |
2023年 | 625篇 |
2022年 | 1899篇 |
2021年 | 2196篇 |
2020年 | 1712篇 |
2019年 | 1490篇 |
2018年 | 1506篇 |
2017年 | 1476篇 |
2016年 | 1743篇 |
2015年 | 2053篇 |
2014年 | 2843篇 |
2013年 | 3020篇 |
2012年 | 2773篇 |
2011年 | 3251篇 |
2010年 | 2697篇 |
2009年 | 2449篇 |
2008年 | 2402篇 |
2007年 | 2546篇 |
2006年 | 2275篇 |
2005年 | 2008篇 |
2004年 | 1768篇 |
2003年 | 1547篇 |
2002年 | 1232篇 |
2001年 | 1191篇 |
2000年 | 963篇 |
1999年 | 864篇 |
1998年 | 761篇 |
1997年 | 778篇 |
1996年 | 635篇 |
1995年 | 638篇 |
1994年 | 601篇 |
1993年 | 479篇 |
1992年 | 356篇 |
1991年 | 305篇 |
1990年 | 273篇 |
1989年 | 248篇 |
1988年 | 234篇 |
1987年 | 171篇 |
1986年 | 145篇 |
1985年 | 289篇 |
1984年 | 183篇 |
1983年 | 136篇 |
1982年 | 121篇 |
1981年 | 102篇 |
1980年 | 73篇 |
1979年 | 58篇 |
1978年 | 51篇 |
1977年 | 31篇 |
1976年 | 31篇 |
1975年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Fumonisins as a possible contributory risk factor for primary liver cancer: A 3-year study of corn harvested in Haimen, China, by HPLC and ELISA 总被引:13,自引:0,他引:13
Y. Ueno K. Iijima S.-D. Wang Y. Sugiura M. Sekijima T. Tanaka C. Chen S.-Z. Yu 《Food and chemical toxicology》1997,35(12):1143-1150
Employing HPLC fluorometry, gas-liquid chromatography (GLC) and a novel enzymelinked immunosorbent assay (ELISA) based on a monoclonal antibody, 40 corn samples, each collected in 1993 from agricultural stocks for human consumption in Haimen (Jiangsu County) and Penlai (Shandong Province), high- and low-risk areas for primary liver cancer (PLC) in China, respectively, were analysed for fumonisins (FBs), aflatoxins (AFs) and trichothecenes. Levels and positive rates of FBs and deoxynivalenol (DON) were significantly higher in Haimen than in Penlai. ELISA of the 40 corn samples harvested in the two areas in 1994 revealed that FB contamination levels and rates in these areas were comparable to those observed in 1993 in Haimen. ELISA analysis of 1993 and 1994 products revealed a wide occurrence of AFB1 but the positive rates as well as levels were not significantly different between these areas. ELISA of the same sample number of corn harvested in 1995 revealed that FB contamination in Haimen was significantly higher than in Penlai. These 3-yearly surveys of corn samples (240 in total) demonstrated that corn harvested in Haimen was highly contaminated with FBs and that the contamination level, as well as positive rate in 1993 and 1995, were 10–50-fold higher than those in Penlai, suggesting FBs as a risk factor for promotion of PLC in endemic areas, along with the trichothecene DON. Co-contamination with AFs, potent hepatocarcinogens, was assumed to play an important role in the initiation of hepatocarcinogenesis. 相似文献
62.
以地高辛甙元随机引物法标记HBV-DNA探针,以此探针检测慢性乙型肝炎患者的血清、肝组织,同时以ELISA法检测血清HBeAg、HBcAb。结果:血清NBeAg阳性率27%(10/37),血清HBV-DNA检出率57.1%(20/35),两者有显著性差异。血清HBcAb阳性率78.4%(29/37),肝组织HBV-DNA检出率83.8%(31/37),两者无显著性差异。血清与肝组织HBV-DNA检出率有显著性差异。提示:血清HBV-DNA检测是较HBeAg更为准确客观反映血液带毒状况的指标。而准确反映肝脏带毒状况的指标是肝组织HBV-DNA检测。当HBeAg阴转,血清HBV-DNA阴性而肝组织HBV-DNA阳性时,需注意肝硬化及肝癌的发生。 相似文献
63.
Pamela E. B. Rodgers-Johnson Frederick W. Hickling Aggrey Irons Bruce K. Johnson Maureen Irons-Morgan Gary A. Stone Clarence J. Gibbs 《Journal of molecular neuroscience : MN》1996,28(1-3):237-243
Reports of an 18-fold higher incidence of schizophrenia among second-generation Afro-Caribbeans, and especially Jamaican migrants
in the United Kingdom were soon called “an epidemic of schizophrenia,” with the inference that a novel virus, likely to be
perinatally transmitted, was a possible etiological agent. This intriguing observation led us to explore a possible link with
human T-cell lymphotropic virus type one (HTLV-I), because it is a virus that is endemic in the Caribbean Islands, is perinatally
transmitted, known to be neuropathogenic, and the cause of a chronic myelopathy (tropical spastic paraparesis/ HTLV-I associated
myelopathy). We therefore examined inpatients at the Bellevue Mental Hospital, Kingston, Jamaica and did standard serological
tests for retroviruses HTLV-I and HTLV-II and HIV-I and HIV-II on 201 inpatients who fulfilled ICD-9 and DSM III-R criteria
for schizophrenia. Our results produced important negative data, since the seropositivity rates for HTLV-I, the most likely
pathogen, were no greater than the seropositivity range for HTLV-I carriers in this island population, indicating that HTLV-I
and the other retroviruses tested do not play a primary etiological role in Jamaican schizophrenics. 相似文献
64.
Masanobu Satake Manabu Inuzuka Katsuya Shigesada Tsuneyuki Oikawa Yoshiaki Ito 《Cancer science》1992,83(7):714-722
The core sequence of the enhancer of murine leukemia virus (MuLV) long terminal repeat is highly conserved in a large number of MuLV strains and appears to play an essential role when SL3-3 or Moloney strains induce T cell lymphoma in mice. We found by using the electrophoretic mobility shift assay that a polyomavirus enhancer core-binding protein, PEBP2, bound to this core motif of MuLV. We also noted that PEBP2 in several hematopoietic cell lines derived from B lymphocyte, macrophage and myelocyte lineages migrated significantly faster than the authentic PEBP2 detected in NIH3T3 (ibroblasts. Interestingly, PEBP2 detected in the cell lines of T lymphocyte lineage appeared to contain both types, which were indistinguishable in electrophoretic mobility from those of NIH3T3 and of B lymphocyte, macrophage and myelocyte lineages. The treatment of the nuclear extract containing PEBP2 with phosphatase generated PEBP3, which is a subcomponent of PEBP2 and retained the same DNA-binding specificity as PEBP2. The altered mobility of hematopoietic cell-derived or T lymphocyte-derived PEBP2 was found to be due to the alteration of the mobility of PEBP3. Based on the distinct mobility of PEBP2/3 of T lymphocytes from those of other hematopoietic cells, we discuss the implication of PEBP2 in MuLV-induced T cell leukemia and T cell-specific gene expression. 相似文献
65.
广东省儿童乙型肝炎疫苗纳入计划免疫管理10年后血清学效果分析 总被引:40,自引:9,他引:31
为研究广东省乙型肝炎 (乙肝 )疫苗纳入计划免疫管理 10年后儿童血清乙肝病毒感染标志物 (HBVM )的变化 ,采用分层多阶段随机抽样法 ,将全省分 4层 ,共抽取 12个县 2 4个村的 196 3名儿童为研究样本。采血用固相放射免疫法 (SPRIA)检测乙肝病毒表面抗原 (HBsAg)、乙肝病毒核心抗体 (抗 HBc)、乙肝病毒表面抗体 (抗 HBs)。2 0 0 2年调查 1~ 14岁儿童乙肝疫苗接种率为 78 81% ,全程接种率为 74 17%。其中 1~ 9岁儿童乙肝疫苗全程接种率为 81 73% ,10~ 14岁为 6 0 32 %。 1~ 14岁儿童HBsAg携带率、抗 HBc阳性率、HBV感染率分别从 1992年的 19 86 %、5 3 5 9%、71 4 1%降至 2 0 0 2年的 8 5 6 %、2 2 5 7%、31 33%。其中 1~ 9岁儿童的HBsAg携带率、抗 HBc阳性率、HBV感染率分别从 1992年的 17 88%、4 7 0 9%、6 7 4 4 %下降至 2 0 0 2年的 5 75 %、14 4 9%、2 1 81%。乙肝疫苗接种后 ,1~ 3岁儿童抗 HBs阳性率为 5 2 0 2 %~ 6 2 18%。由于实施了加强免疫 ,4~ 14岁儿童的抗 HBs维持在 5 9 32 %~ 6 5 80 %。广东省乙肝疫苗纳入计划免疫管理 10年后 ,全省 1~ 14岁儿童HBV感染率已大幅度下降 ,抗 HBs阳性率大幅度升高 ,取得了良好的经济和社会效益。 相似文献
66.
Iain L. Campbell 《Journal of neuroimmunology》1996,71(1-2)
To elucidate the possible involvement of the inducible nitric oxide synthase (iNOS) and NO in the development of lymphocytic choriomeningitis (LCM), the consequences of inhibition of iNOS by the inhibitor aminoguanidine was examined in mice following intracerebral infection with LCM virus (LCMV). Aminoguanidine administration to mice infected with LCMV completely blocked increased plasma nitrate/nitrite levels and led to increased proinflammatory cytokine gene expression at early stages of lesion development in the brain, enhanced clinical severity and decreased survival time. The levels of LCMV recovered from the brain of aminoguanidine treated mice did not differ from those in infected control mice. These findings argue against either an anti-viral or pathogenic role of NO in LCM but rather suggest a possible protective action of this mediator. 相似文献
67.
68.
69.
70.
Nobutaka Eiraku Shinji Ijichi Shinji Yashiki Mitsuhiro Osame Shunro Sonoda 《Journal of neuroimmunology》1992,37(3):223-228
The in vitro proliferation of peripheral blood lymphocytes (PBLs) without any mitogenic stimulation is one of the hallmarks of human T lymphotropic virus type I (HTLV-I) infection. Recent evidence suggests a difference in the degree of the phenomenon between HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and asymptomatic HTLV-I carriers (AC). In this article, we demonstrated several alterations in the features of the in vitro transformed lymphocytes between patients with HAM/TSP (n = 16) and AC (n = 8). The percentages of total CD8+ and CD8+CD28+ cells were significantly increased in the in vitro proliferating T lymphocytes derived from the patients with HAM/TSP when compared to those from AC. HAM/TSP was segregated from AC by the high degree of the proliferation of CD8+CD28+ cells. The expression of HTLV-I-specific antigens on the cultured PBLs was detected only in the subjects which showed low CD8+CD28+/CD4+ ratio of the in vitro proliferating lymphocytes. These findings suggest that this phenomenon distinguishes HAM/TSP from AC, not only in quantity but also in quality. 相似文献