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51.
Zagzag D Salnikow K Chiriboga L Yee H Lan L Ali MA Garcia R Demaria S Newcomb EW 《Laboratory investigation; a journal of technical methods and pathology》2005,85(3):328-341
Invasion into surrounding brain tissue is a fundamental feature of gliomas and the major reason for treatment failure. The process of brain invasion in gliomas is not well understood. Differences in gene expression and/or gene products between invading and noninvading glioma cells may identify potential targets for new therapies. To look for genes associated with glioma invasion, we first employed Affymetrix microarray Genechip technology to identify genes differentially expressed in migrating glioma cells in vitro and in invading glioma cells in vivo using laser capture microdissection. We observed upregulation of a variety of genes, previously reported to be linked to glioma cell migration and invasion. Remarkably, major histocompatiblity complex (MHC) class I and II genes were significantly downregulated in migrating cells in vitro and in invading cells in vivo. Decreased MHC expression was confirmed in migrating glioma cells in vitro using RT-PCR and in invading glioma cells in vivo by immunohistochemical staining of human and murine glioblastomas for beta2 microglobulin, a marker of MHC class I protein expression. To the best of our knowledge, this report is the first to describe the downregulation of MHC class I and II antigens in migrating and invading glioma cells, in vitro and in vivo, respectively. These results suggest that the very process of tumor invasion is associated with decreased expression of MHC antigens allowing glioma cells to invade the surrounding brain in a 'stealth'-like manner. 相似文献
52.
PCR-based detection of Bacillus anthracis in formalin-fixed tissue from a patient receiving ciprofloxacin 总被引:3,自引:0,他引:3 下载免费PDF全文
Levine SM Perez-Perez G Olivares A Yee H Hanna BA Blaser MJ 《Journal of clinical microbiology》2002,40(11):4360-4362
We demonstrate that Bacillus anthracis may be detected from a formalin-fixed, paraffin-embedded biopsy specimen, even after the patient has received antibiotic treatment. Although traditional PCR methods may not be sufficiently sensitive for anthrax detection in such patients, cycle numbers can be increased or PCR can be repeated by using an aliquot from a previous PCR as the template. 相似文献
53.
Lai PS Takeshima Y Adachi K Van Tran K Nguyen HT Low PS Matsuo M 《Journal of human genetics》2002,47(10):0552-0555
The frequency and distribution of deletions of 19 deletion-prone exons clustered in two hot spots in the proximal and central
regions of the dystrophin gene were compared in three populations from Singaporean, Japan, and Vietnam. DNA samples obtained
from 105 Singaporean, 86 Japanese, and 34 Vietnamese Duchenne muscular dystrophy patients were examined by polymerase chain
reaction amplification. Deletions of the examined exons were found in 51.2% of Japanese patients but in 40.0% or less of the
Singaporeans and Vietnamese. About two thirds of the deletions were localized in the central region and the remaining deletions
were clustered at the proximal region. The most commonly deleted exons at the central deletion hot spot were exon 50 in the
Singaporean, exons 49 and 50 in the Japanese, and exon 51 in the Vietnamese population. At the proximal deletion hot spot,
the most commonly deleted exons were exons 6 and 8 in the Singaporeans, exons 12 and 17 in the Japanese, and exons 8 and 12
in the Vietnamese. Two cases each from Singapore and Japan had large-scale gross mutations spanning both deletion hot spots.
Our results suggest that, although the presence and frequency of the two deletion hot spots may be similar in the three Asian
populations analyzed, the distribution and frequency of deletions among the different exons can vary as a result of population-specific
intronic sequences that predispose individuals to preferential deletion breakpoints.
Received: May 20, 2002 / Accepted: July 1, 2002 相似文献
54.
SARS病毒S1蛋白重组C端片段免疫效果的实验研究 总被引:1,自引:0,他引:1
为获得纯化的重组SARS病毒S1蛋白C端 ,研究其刺激机体产生针对SARS病毒免疫应答的规律和机制 ,将编码SARS病毒S1蛋白C端 311个氨基酸残基的基因克隆 ,并在原核表达系统中表达 ,纯化获得了的重组蛋白。利用SARS患者恢复期的血清 ,对纯化的重组S1蛋白进行血清学分析。结果表明 ,本研究中克隆表达的重组蛋白序列与公布的SARS病毒S1蛋白C端的序列相同 ,其编码的重组蛋白相对分子质量约为 5 90 0 0Mr。SARS患者恢复期的血清均与重组蛋白反应 ,在5 9 0 0 0Mr处形成特异性的反应条带 ,而来自SARS流行前的正常人对照血清则不能与重组蛋白反应。在本研究中获得的重组蛋白可以为研究SARS病毒识别宿主细胞受体的过程及其机制提供条件。 相似文献
55.
56.
Bannerman DM Lemaire M Yee BK Iversen SD Oswald CJ Good MA Rawlins JN 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2002,142(3):395-401
Although a number of studies have implicated the hippocampal formation in social recognition memory in the rat, a recent study in this laboratory has demonstrated that selective cytotoxic lesions, confined to the hippocampus proper (encompassing the four CA subfields and the dentate gyrus), are without effect on this behaviour. This finding suggests that the hippocampus proper does not subserve social recognition memory in the rat, but does not preclude the possibility that other areas of the hippocampal formation, such as the entorhinal cortex or subiculum, could support this form of learning. The present study addressed this issue by examining the effects of selective cytotoxic retrohippocampal (RHR) lesions (including both the entorhinal cortex and subiculum) on social recognition memory in the rat. RHR lesions produced a mild social recognition memory impairment, although lesioned animals still displayed a reduction in investigation time between the first and second exposure to the juvenile. This result is consistent with other studies which have implicated the retrohippocampal or parahippocampal area in olfactory recognition memory processes. It also suggests, however, that other areas, out with the retrohippocampal region, are also likely to play an important role in social recognition memory. 相似文献
57.
The data presented show that the blastogenic response of human peripheral lymphocytes to mitogens and specific antigens can be easily evaluated with rapid flow analysis of mithramycin stained cells. The precision, reproducibility and rapidity of the method make it highly suitable to study lymphocyte response to antigens in patient populations. 相似文献
58.
Meora Feinmesser Sylvia L. Asa Kaiman Kovacs Bernard A. Roos Malcolm J. Low 《Endocrine pathology》1992,3(1):39-46
Clonal cell lines producing corticotropin-releasing hormone (CRH) have been generated by transfection of the W2 rat medullary
thyroid carcinoma (MTC) cell with a CRH-encoding CMV/ SV40 expression vector. Here, we report the morphological, immunohistochemical,
and ultrastructural features of rat tumors derived by implantation of CRH-producing W2CRH-7 cells and compare them with non-CRH-producing
W2 MTCs. Both types of tumors grew rapidly and consisted of sheets and nests of pleomorphic cells infiltrating adjacent adipose
tissue. Immunohistochemistry revealed CRH in only W2CRH-7 tumors; scattered cells in these tumors also were immunoreactive
for chromogranin and for vasoactive intestinal peptide. Otherwise, the two tumor types exhibited similar profiles of various
neuroendocrine markers, including neuron-specific enolase, synaptophysin, calcitonin, and somatostatin. Ultrastructurally,
the tumors contained abundant dilated rough endoplasmic reticulum, a prominent Golgi apparatus, and numerous lysosomes. Very
few secretory granules were noted in the W2 tumors; by contrast, secretory granules, although still not numerous in the majority
of W2CRH-7 cells, were more abundant in scattered cells of those tumors. The positive immunostaining for CRH is consistent
with the observations of increased plasma CRH and pituitary-adrenal activation induced by these transplanted tumors. This
system provides a valuable model for CRH excess mimicking tumoral CRH-dependent Cushing’s syndrome in human patients. 相似文献
59.
Woodward MJ Best A Sprigings KA Pearson GR Skuse AM Wales A Hayes CM Roe JM Low JC La Ragione RM 《International journal of medical microbiology : IJMM》2003,293(4):299-308
Ruminants are regarded as a primary reservoir for Escherichia coli O157:H7, an important human pathogen. Intimin, encoded by the Locus of Enterocyte Effacement by E. coli O157:H7 organisms, has been cited as one bacterial mechanism of colonisation of the gastrointestinal tract. To confirm this and to test whether a non-toxigenic E. coli O157:H7 strain would colonise and persist in a sheep model, E. coli O157:H7 strain NCTC12900, that lacks Shiga toxin (stx) genes, was evaluated for use in a sheep model of persistence. Following oral inoculation of six-week-old sheep, persistent excretion of NCTC12900 was observed for up to 48 days. E. coli O157-associated attaching-effacing (AE) lesions were detected in the caecum and rectum of one six-week-old lamb, one day after inoculation. This is the first recorded observation of AE lesions in orally inoculated weaned sheep. Also, mean faecal excretion scores of NCTC12900 and an isogenic intimin (eae)-deficient mutant were determined from twenty-four six-week-old orally inoculated sheep. The eae mutant was cleared within 20 days and had lower mean excretion scores at all time points after day one post inoculation compared with the parental strain that was still being excreted at 48 days. Tissues were collected post mortem from animals selected at random from the study groups over the time course of the experiment. The eae mutant was detected in only 1/43 samples but the parental strain was recovered from 64/140 samples primarily from the large bowel although rumen, duodenum, jejunum, and ileum were culture positive especially from animals that were still excreting at and beyond 27 days after inoculation. 相似文献
60.
Antigen-specific suppression of a primed immune response by dendritic cells mediated by regulatory T cells secreting interleukin-10 总被引:23,自引:0,他引:23
Antigen-specific suppression of a previously primed immune response is a major challenge for immunotherapy of autoimmune disease. RelB activation is required for myeloid DC differentiation. Here, we show that antigen-exposed DCs in which RelB function is inhibited lack cell surface CD40, prevent priming of immunity, and suppress previously primed immune responses. DCs generated from CD40-deficient mice similarly confer suppression. Regulatory CD4+ T cells induced by the DCs transfer antigen-specific "infectious" tolerance to primed recipients in an interleukin-10-dependent fashion. Thus CD40, regulated by RelB activity, determines the consequences of antigen presentation by myeloid DCs. These observations have significance for autoimmune immunotherapy and suggest a mechanism by which peripheral tolerance might be constitutively maintained by RelB(-) CD40(-) DCs. 相似文献