全文获取类型
收费全文 | 4735篇 |
免费 | 415篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 132篇 |
妇产科学 | 64篇 |
基础医学 | 841篇 |
口腔科学 | 11篇 |
临床医学 | 549篇 |
内科学 | 1451篇 |
皮肤病学 | 17篇 |
神经病学 | 76篇 |
特种医学 | 18篇 |
外科学 | 104篇 |
综合类 | 55篇 |
现状与发展 | 1篇 |
预防医学 | 1658篇 |
眼科学 | 8篇 |
药学 | 128篇 |
中国医学 | 1篇 |
肿瘤学 | 35篇 |
出版年
2024年 | 8篇 |
2023年 | 320篇 |
2022年 | 224篇 |
2021年 | 243篇 |
2020年 | 502篇 |
2019年 | 295篇 |
2018年 | 246篇 |
2017年 | 235篇 |
2016年 | 232篇 |
2015年 | 292篇 |
2014年 | 276篇 |
2013年 | 174篇 |
2012年 | 129篇 |
2011年 | 102篇 |
2010年 | 179篇 |
2009年 | 147篇 |
2008年 | 98篇 |
2007年 | 111篇 |
2006年 | 132篇 |
2005年 | 163篇 |
2004年 | 141篇 |
2003年 | 164篇 |
2002年 | 138篇 |
2001年 | 177篇 |
2000年 | 145篇 |
1999年 | 117篇 |
1998年 | 48篇 |
1997年 | 29篇 |
1996年 | 35篇 |
1995年 | 13篇 |
1994年 | 18篇 |
1993年 | 12篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1986年 | 1篇 |
排序方式: 共有5155条查询结果,搜索用时 62 毫秒
61.
McCaustland KA Krawczynski K Ebert JW Balayan MS Andjaparidze AG Spelbring JE Cook EH Humphrey C Yarbough PO Favorov MO Carson D Bradley DW Robertson BH 《Archives of virology》2000,145(9):1909-1918
Summary. Different patterns of disease were observed among 11 chimpanzees who were inoculated intravenously with hepatitis E virus
(HEV) positive fecal specimens from four different outbreaks (Nepal 1981, Uzbekistan 1981, Pakistan 1985, and Mexico 1986).
Five chimpanzees had marginal or no liver enzyme elevations within 70 days of inoculation. Two of the chimpanzees had limited
viremia, but did not produce detectable antibody. The four remaining chimpanzees had liver enzyme elevations, viral shedding,
viremia, seroconversion to anti-HEV, and detectable HEV antigen in liver biopsy specimens. These results may reflect the range
of infection patterns that develop in humans after natural exposure to the HEV.
Received December 29, 1999/Accepted February 21, 2000 相似文献
62.
Comparative evaluation of PASCO and national committee for clinical laboratory standards M27-A broth microdilution methods for antifungal drug susceptibility testing of yeasts 总被引:1,自引:0,他引:1 下载免费PDF全文
Arthington-Skaggs BA Motley M Warnock DW Morrison CJ 《Journal of clinical microbiology》2000,38(6):2254-2260
The PASCO antifungal susceptibility test system, developed in collaboration with a commercial company, is a broth microdilution assay which is faster and easier to use than the reference broth microdilution test performed according to the National Committee for Clinical Laboratory Standards (NCCLS) document M27-A guidelines. Advantages of the PASCO system include the system's inclusion of quality-controlled, premade antifungal panels containing 10, twofold serial dilutions of drugs and a one-step inoculation system whereby all wells are simultaneously inoculated in a single step. For the prototype panel, we chose eight antifungal agents for in vitro testing (amphotericin B, flucytosine, fluconazole, ketoconazole, itraconazole, clotrimazole, miconazole, and terconazole) and compared the results with those of the NCCLS method for testing 74 yeast isolates (14 Candida albicans, 10 Candida glabrata, 10 Candida tropicalis, 10 Candida krusei, 10 Candida dubliniensis, 10 Candida parapsilosis, and 10 Cryptococcus neoformans isolates). The overall agreements between the methods were 91% for fluconazole, 89% for amphotericin B and ketoconazole, 85% for itraconazole, 80% for flucytosine, 77% for terconazole, 66% for miconazole, and 53% for clotrimazole. In contrast to the M27-A reference method, the PASCO method classified as resistant seven itraconazole-susceptible isolates (9%), two fluconazole-susceptible isolates (3%), and three flucytosine-susceptible isolates (4%), representing 12 major errors. In addition, it classified two fluconazole-resistant isolates (3%) and one flucytosine-resistant isolate (1%) as susceptible, representing three very major errors. Overall, the agreement between the methods was greater than or equal to 80% for four of the seven species tested (C. dubliniensis, C. glabrata, C. krusei, and C. neoformans). The lowest agreement between methods was observed for miconazole and clotrimazole and for C. krusei isolates tested against terconazole. When the data for miconazole and clotrimazole were removed from the analysis, agreement was >/=80% for all seven species tested. Therefore, the PASCO method is a suitable alternative procedure for the testing of the antifungal susceptibilities of the medically important Candida spp. and C. neoformans against a range of antifungal agents with the exceptions only of miconazole and clotrimazole and of terconazole against C. krusei isolates. 相似文献
63.
Nigel A. Cunliffe Bimal K. Das Madhumati Ramachandran Maharaj K. Bhan Roger I. Glass Jon R. Gentsch 《Virus genes》1997,15(1):39-44
We have sequenced the genes encoding the inner capsid protein VP6 and the nonstructural proteins NSP1 and NSP4 of the Indian
neonatal serotype P8[11]G9 human/bovine reassortant candidate vaccine rotavirus strain 116E. These three genes share a high
degree of sequence and deduced amino acid homology with human prototype strain Wa. Our results confirm and extend those of
previous RNA-RNA hybridization studies which suggested that these genes are of human origin, and will facilitate examination
of the host immune response to 116E induced by natural infection and vaccination.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
64.
65.
Comparison of disseminated and nondisseminated strains of Borrelia burgdorferi sensu stricto in mice naturally infected by tick bite 下载免费PDF全文
Dolan MC Piesman J Schneider BS Schriefer M Brandt K Zeidner NS 《Infection and immunity》2004,72(9):5262-5266
Clinical isolates of Borrelia burgdorferi sensu stricto have been categorized into disseminated and nondisseminated groups based on distinct ribosomal spacer restriction fragment length polymorphism genotypes (RSTs). In order to determine whether transmission by tick bite would alter the dissemination dynamics and disease produced by distinct genotypes, disseminated isolates (RST1), nondisseminated isolates (RST3), and a standard laboratory strain (B-31) were established in a murine cycle utilizing infections transmitted by ticks. B-31 spirochetes circulated in the blood of inbred C3H/HeJ mice longer than in the blood of outbred mice. The majority of C3H mice exposed to RST1-infected ticks contained cultivable spirochetes in their blood for up to 17 days; in contrast, mice exposed to RST3 isolates demonstrated a precipitous decline in infection after day 7 postexposure. A quantitative PCR (q-PCR) assay demonstrated that the densities of spirochetes in blood were similar for the RST1 and RST3 isolates, except during the 2nd week postexposure, when the RST1 isolates displayed a markedly higher density in blood. Spirochete load in the heart and bladder of infected mice was measured by q-PCR at 8 weeks postexposure; the numbers of spirochetes in these tissues were similar for mice infected with either disseminated or nondisseminated strains. Similarly, histopathology samples of heart, bladder, and joint tissue obtained at 8 weeks postexposure did not reveal greater pathology in mice infected with the disseminated isolates. We conclude that although the spirochetemia induced by tick-transmitted disseminated isolates was more intense and of longer duration than that induced by nondisseminated isolates, the resultant pathologies produced by these strains were ultimately similar. 相似文献
66.
Chaisavaneeyakorn S Moore JM Mirel L Othoro C Otieno J Chaiyaroj SC Shi YP Nahlen BL Lal AA Udhayakumar V 《Clinical and diagnostic laboratory immunology》2003,10(4):631-636
Macrophage inflammatory protein-1 alpha (MIP-1 alpha) and MIP-1 beta play an important role in modulating immune responses. To understand their importance in immunity to placental malaria (PM) and in human immunodeficiency virus (HIV)-PM coinfection, we investigated levels of these chemokines in the placental intervillous blood plasma (IVB plasma) and cord blood plasma of HIV-negative PM-negative, HIV-negative PM-positive, HIV-positive PM-negative, and HIV-positive PM-positive women. Compared to HIV-negative PM-negative women, the MIP-1 beta concentration in IVB plasma was significantly elevated in HIV-negative PM-positive women and HIV-positive PM-positive women, but it was unaltered in HIV-positive PM-negative women. Also, PM-infected women, irrespective of their HIV status, had significantly higher levels of MIP-1 beta than HIV-positive PM-negative women. The MIP-1 alpha level was not altered in association with either infection. The IVB plasma levels of MIP-1 alpha and MIP-1 beta positively correlated with the cord blood plasma levels of these chemokines. As with IVB plasma, only cord plasma from PM-infected mothers had significantly elevated levels of MIP-1 beta compared to PM-negative mothers, irrespective of their HIV infection status. MIP-1 beta and MIP-1 alpha levels in PM-positive women were positively associated with parasite density and malaria pigment levels. Regardless of HIV serostatus, the IVB MIP-1 beta level was significantly lower in women with PM-associated anemia. In summary, an elevated level of MIP-1 beta was associated with PM. HIV infection did not significantly alter these two chemokine levels in IVB plasma. 相似文献
67.
James F Jones Elizabeth M Maloney Roumiana S Boneva Ann-Britt Jones William C Reeves 《BMC complementary and alternative medicine》2007,7(1):12
Background
Chronic fatiguing illnesses, including chronic fatigue syndrome (CFS), pose a diagnostic and therapeutic challenge. Previous clinical reports addressed the utilization of health care provided to patients with CFS by a variety of practitioners with other than allopathic training, but did not examine the spectrum of complementary and alternative medicine (CAM) therapies used. This study was designed to measure CAM therapy use by persons with fatiguing illnesses in the United States population. 相似文献68.
69.
《Ticks and Tick》2022,13(1):101843
The genome of Borrelia spp. consists of an approximate 1 megabase chromosome and multiple linear and circular plasmids. We previously described a multiplex PCR assay to detect plasmids in the North American Borrelia miyamotoi strains LB-2001 and CT13–2396. The primer pair sets specific for each plasmid were derived from the genome sequence for B. miyamotoi strain CT13–2396, because the LB-2001 complete sequence had not been generated. The recent completion of the LB-2001 genome sequence revealed a distinct number of plasmids (n = 12) that differed from CT13–2396 (n = 14). Notable was a 97-kilobase plasmid in LB-2001, not present in CT13–2396, that appeared to be a rearrangement of the circular plasmids of strain CT13–2396. Strain LB-2001 contained two plasmids, cp30–2 and cp24, that were not annotated for strain CT13–2396. Therefore, we re-evaluated the original CT13–2396-derived multiplex PCR primer pairs and determined their location in the LB-2001 plasmids. We modified the original multiplex plasmid PCR assay for strain LB-2001 to include cp30–2 and cp24. We also determined which LB-2001 plasmids corresponded to the amplicons generated from the original CT13–2396 primer sets. These observations provide a more precise plasmid profile based on the multiplex PCR assay and reflect the complexity of gene rearrangements that occur in B. miyamotoi strains isolated from the same geographic region. 相似文献
70.
《Ticks and Tick》2022,13(6):102053
Ixodes ricinus ticks are considered as the vector of the Borrelia burgdorferi sensu lato complex in urban areas, including city parks and green recreational areas. The aim of the present study was to determine the prevalence of B. burgdorferi s. l. in urban areas in the city of Prague, Czech Republic. In selected public green areas in Prague, a total of 2819 I. ricinus ticks were collected in spring, from April to June, in 2014-2020. Quantitative real time PCR revealed 28.1% of ticks (31% of males, 33.7% of females and 25.8% of nymphs) to be positive for B. burgdorferi s. l. The prevalence varied significantly (p?0.01) between collection sites, with the highest numbers of infected ticks found in the central city areas. The places serving people for recreational and sport activities in urban areas are characterized by a lower diversity of reservoir hosts, provide opportunity for exposure to Borrelia infected ticks, and pose a higher infection risk. We have detected seven Borrelia species in ticks: B. garinii, B. afzelii, B. bavariensis, B. burgdorferi sensu stricto, B. valaisiana, B. spielmanii, and B. finlandensis. Most positive ticks were infected by B. garinii (35%) and B. afzelii (36.9%). Our results show that the Borrelia transmission cycle occurs within urban biotops and highlight the need for surveillance of tick-borne pathogens in public green areas. 相似文献