全文获取类型
收费全文 | 173046篇 |
免费 | 9951篇 |
国内免费 | 436篇 |
专业分类
耳鼻咽喉 | 2277篇 |
儿科学 | 5558篇 |
妇产科学 | 3631篇 |
基础医学 | 23489篇 |
口腔科学 | 7788篇 |
临床医学 | 12616篇 |
内科学 | 38862篇 |
皮肤病学 | 4376篇 |
神经病学 | 14454篇 |
特种医学 | 5310篇 |
外国民族医学 | 26篇 |
外科学 | 21217篇 |
综合类 | 1387篇 |
现状与发展 | 1篇 |
一般理论 | 60篇 |
预防医学 | 17989篇 |
眼科学 | 3232篇 |
药学 | 10529篇 |
中国医学 | 720篇 |
肿瘤学 | 9911篇 |
出版年
2023年 | 904篇 |
2022年 | 2000篇 |
2021年 | 3720篇 |
2020年 | 2475篇 |
2019年 | 3495篇 |
2018年 | 4945篇 |
2017年 | 3676篇 |
2016年 | 3423篇 |
2015年 | 4045篇 |
2014年 | 5543篇 |
2013年 | 6989篇 |
2012年 | 10861篇 |
2011年 | 11368篇 |
2010年 | 5740篇 |
2009年 | 5149篇 |
2008年 | 8782篇 |
2007年 | 9375篇 |
2006年 | 8687篇 |
2005年 | 8943篇 |
2004年 | 8423篇 |
2003年 | 7689篇 |
2002年 | 5727篇 |
2001年 | 4982篇 |
2000年 | 4993篇 |
1999年 | 4373篇 |
1998年 | 1550篇 |
1997年 | 1282篇 |
1996年 | 1275篇 |
1995年 | 1088篇 |
1994年 | 1076篇 |
1993年 | 981篇 |
1992年 | 2670篇 |
1991年 | 2570篇 |
1990年 | 2344篇 |
1989年 | 2342篇 |
1988年 | 2111篇 |
1987年 | 1959篇 |
1986年 | 1834篇 |
1985年 | 1756篇 |
1984年 | 1261篇 |
1983年 | 1010篇 |
1982年 | 566篇 |
1981年 | 513篇 |
1980年 | 494篇 |
1979年 | 927篇 |
1978年 | 608篇 |
1977年 | 479篇 |
1975年 | 543篇 |
1974年 | 540篇 |
1973年 | 542篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
Identification of two homologous antigenic peptides derived from L1 HPV-16 and 18 proteins specific for the HLA-B*3901 allele 总被引:1,自引:0,他引:1
Monroy-García A Weiss-Steider B Hernández-Montes J Ortiz-Navarrete VF Bañuelos-Pánuco A Acosta-Araujo A Díaz-Quiñónez A López-Graniel CM Herbert G Granados J de Leo C Silva-López RM Mora-García ML 《Archives of virology》2002,147(10):1933-1942
Summary. In this work we present evidence that the homologous peptides IHSMNSTIL and IHSMNSSIL derived from L1 HPV-16 and 18 proteins
respectively, and with high specificity for the allele HLA-B*3901, according with an algorithm prediction program, induced T cell stimulation in patients with advanced cervical cancer
positive for HPV-16 or 18 infection and for the HLA-B*3901 allele. Interestingly, T lymphocytes derived from a patient with HPV-18 infection and stimulated with the peptide IHSMNSTIL
were capable to kill a cervical cancer cell line named Rova, derived from the tumor of the same patient. In addition, the
cytotoxic activity was strongly increased when this cell line was previously treated with hrIFN-γ. These results suggest that
the CTL immune response to L1 HPV-16 and 18 protein derived epitopes is maintained in patients with advanced cervical cancer
within specific alleles, and opens the possibility that homologous epitopes may be used in the generation of prophylactic
vaccines for cervical tumors bearing different HPV-types.
Received March 4, 2002; accepted May 20, 2002 相似文献
962.
Nevalainen TJ Shah VI de Peralta-Venturina M Amin MB 《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》2001,109(4):295-298
Paneth cell-like metaplasia has been reported in the epithelium of the epididymis and prostatic adenocarcinomas. We studied the expression of group II phospholipase A2 (PLA2), a marker of Paneth cell differentiation, in six orchiectomy specimens with Paneth cell-like metaplasia. Both immunohistochemistry for group II PLA2 protein and in situ hybridization for the mRNA of group II PLA2 gave negative results in all six cases but positive reaction for lysozyme. The results show that the cells of the Paneth cell-like metaplasia are not true Paneth cells. 相似文献
963.
Yokoyama T Pruchnic R Lee JY Chuang YC Jumon H Yoshimura N de Groat WC Huard J Chancellor MB 《Tissue engineering》2001,7(4):395-404
The goal of these experiments was to establish the basic methodology for future clinical applications of muscle-derived cells (MDC) tissue engineering and gene transfer for the treatment of urological dysfunction. Primary MDC isolated via preplating techniques from adult female SD rats were transduced with retrovirus encoding the expression of beta-galactosidase reporter gene. The MDC were injected into the right and left lateral walls of the bladder and proximal urethra of the autologous animals (n = 6) with a 10 microl Hamilton micro syringe. The amount of injected MDC ranged from 1 to 2 x 10(6) cells. The injected tissue was harvested after 7, 14, and 28 days, sectioned and examined histologically for beta-galactosidase and immunohistochemically for fast myosin heavy chain specific to skeletal muscle. The tissues were also stained for anti-CD4 and anti-CD8 antibodies to assess for cellular immune reaction. We have detected a large number of autologous MDC expressing beta-galactosidase and positively stained for fast myosin heavy chain in the bladder and urethral wall. Many injected myoblasts and myotubes were also seen in the bladder and urethral wall at each time point. Staining of lymphocytes with anti-CD4 and anti-CD8 antibodies was negative after MDC injection at each time point. We have demonstrated the long-term survival of autologous MDC and MDC mediated gene transfer into the bladder and urethral wall. Autologous MDC and MDC mediated gene transfer may be a promising treatment to augment bladder and urethral sphincter function. 相似文献
964.
Rubn F. Iacono Analia Nessi de Avin Francisco A. Rosetti María I. Berría 《Neuroscience letters》1995,200(3):175-178
After five steps of purification including gel permeation, anti-angiotensin I affinity column chromatography followed by reverse-phase HPLC, a peptide immunoreactive to two different antisera (anti-angiotensin I) was purified to homogeneity from extracts of the leech Theromyzon tessulatum. The first 14 amino acid residues of the purified peptide (DRVYIHPFLLXWG) established by automated Edman degradation, reveal the existence in leeches of an angiotensin I-like molecule close to human angiotensin I. The sequence of the purified peptide presents 78.5% of homology with the N-terminal part of human angiotensin. Moreover, in its sequence, this peptide presents the cleavage sites of vertebrate angiotensin metabolic enzymes, i.e. the renin and the angiotensin-converting enzyme. This finding constitutes the first biochemical characterization of an angiotensin I in Invertebrates. It also reflects the high conservation of angiotensins in the course of evolution, suggesting a fundamental role of this family in fluid homeostasis. 相似文献
965.
Towards a novel classification of human malignancies based on gene expression patterns 总被引:12,自引:0,他引:12
As a result of progress on the human genome project, approximately 19 000 genes have been identified and tens of thousands more tentatively identified as partial fragments of genes termed expressed sequence tags (ESTs). Most of these genes are only partially characterized and the functions of the vast majority are as yet unknown. It is likely that many genes that might be useful for diagnosis and/or prognostication of human malignancies have yet to be recognized. The advent of cDNA microarray technology now allows the efficient measurement of expression for almost every gene in the human genome in a single overnight hybridization experiment. This genomic scale approach has begun to reveal novel molecular-based sub-classes of tumours in breast carcinoma, colon carcinoma, lymphoma, leukaemia, and melanoma. In several instances, gene microarray analysis has already identified genes that appear to be useful for predicting clinical behaviour. This review discusses some recent findings using gene microarray technology and describes how this and related technologies are likely to contribute to the emergence of novel molecular classifications of human malignancies. 相似文献
966.
967.
Hoogenboom LAP de Haan L Hooijerink D Bor G Murk AJ Brouwer A 《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》2001,109(2):101-107
A number of metabolites of 17beta-estradiol were tested for their estrogenic activity using the ER-CA-LUX assay based on the increased expression of luciferase in exposed T47D breast cancer cells. E2beta and estrone showed similar potencies in the test, whereas E2alpha was 100 times less active. Incubation of cells with estrone (0.35 microM) resulted in the formation of E2beta, whereas the reverse reaction was observed for E2beta. The resulting equilibrium may explain the similar estrogenic potency of estrone in the test. The synthetic 17-hydroxy benzoate ester of E2beta was 3 times less active than the parent compound. The 17-hydroxy palmitate and oleate esters of E2beta, were respectively 25 and 200 times less active than the parent compound. The 2-hydroxy metabolites of E2beta and estrone showed a 5,000 to 10,000 fold lower activity. The 4-hydroxy metabolites were more potent than the 2-hydroxy metabolites, showing only a 20-200 times lower activity. The 2- and 4-methoxyesters of estrone were 700 times less active. It is concluded that the estrogenic potency of metabolites formed in cattle after treatment with E2beta, like estrone, E2alpha and especially the esters of E2beta, may be significant with respect to the potential risk of the use of estradiol for growth promotion in domestic animals in certain countries. 相似文献
968.
The survival of skin penetrating cercariae depends on information on the direction to move toward deeper layers in the epidermis (the direction of further migration) and toward the surface (direction which must be avoided when migrating). We tested the hypothesis that parasites can use their photo-sensitivity for orientation away from the light-exposed skin surface towards darker locations. Cercariae of species invading humans (Schistosoma mansoni), birds (Trichobilharzia ocellata) and fish (Diplostomum spathaceum) oriented towards light sources when free swimming in cuvettes. However, they shifted to a negative photo-orientation when migrating in agar substrates after penetration and transformation to schistosomula. This is a first hint that parasites may use photo-orientation when they navigate in host tissues. 相似文献
969.
The novel HLA-Cw*1802 allele is associated with B*5703 in the Bubi population from Equatorial Guinea
C. Vilches M. Bunce R. de Pablo M. E. Moreno S. Puente L. Sanz M. Kreisler 《Tissue antigens》1997,49(6):644-648
The HLA-Cw*1801 specificity, a Cw7/Cw4 hybrid allele, has recently been described in association with B*8101 (formerly B"DT"). In this study, the new Cw*1802 variant, differing from Cw*1801 at exon 5. is found associated with B*5703 in Bubi individuals from Equatorial Guinea. Confirmatory complete coding regions of B*5703 and B*3910 are also reported. 相似文献
970.
Femoral implantation of regenerated cellulose hydrogels revealed their biocompatibility, but a complete osseointegration could not be observed. Phosphorylation was therefore envisaged as the means to enhance cellulose bioactivity. In vitro studies showed that regenerated cellulose hydrogels promote bone cells attachment and proliferation but do not mineralize in acellular simulated physiological conditions. On the contrary, phosphorylated cellulose has shown an opposite behavior, by inducing the formation of a calcium phosphate layer in simulated physiological conditions, but behaving as a poor substrate for bone cells attachment and proliferation. In order to investigate the in vivo behavior of these materials, and assess the influence of mineralization induction ability vs. bone cells compatibility, unmodified and phosphorylated cellulose hydrogels were implanted in rabbits for a maximum period of 6 months and bone regeneration was investigated. Despite the difficulties arising from the retraction of cellulose hydrogels upon dehydration during the preparation of retrieved implants, histological observations showed no inflammatory response after implantation, with bone intra-spongious regeneration of cells and the integration of the unmodified as well as the phosphorylated cellulose implants. After a maximum implantation period of 6 months, histological observations, histomorphometry and the measurement of the amount of 45Ca incorporated in the surrounding tissue indicated a slightly better osseointegration of phosphorylated cellulose, although no significant differences between the two materials were found. 相似文献