全文获取类型
收费全文 | 120095篇 |
免费 | 9553篇 |
国内免费 | 2996篇 |
专业分类
耳鼻咽喉 | 1245篇 |
儿科学 | 7181篇 |
妇产科学 | 3801篇 |
基础医学 | 13578篇 |
口腔科学 | 1569篇 |
临床医学 | 13032篇 |
内科学 | 20513篇 |
皮肤病学 | 2364篇 |
神经病学 | 10481篇 |
特种医学 | 2677篇 |
外国民族医学 | 3篇 |
外科学 | 11027篇 |
综合类 | 17136篇 |
现状与发展 | 15篇 |
预防医学 | 6835篇 |
眼科学 | 2186篇 |
药学 | 6136篇 |
51篇 | |
中国医学 | 11041篇 |
肿瘤学 | 1773篇 |
出版年
2024年 | 227篇 |
2023年 | 2058篇 |
2022年 | 3313篇 |
2021年 | 5863篇 |
2020年 | 5351篇 |
2019年 | 4242篇 |
2018年 | 4283篇 |
2017年 | 4395篇 |
2016年 | 4510篇 |
2015年 | 4298篇 |
2014年 | 8387篇 |
2013年 | 8660篇 |
2012年 | 6829篇 |
2011年 | 7955篇 |
2010年 | 6156篇 |
2009年 | 5970篇 |
2008年 | 5799篇 |
2007年 | 5916篇 |
2006年 | 5329篇 |
2005年 | 4413篇 |
2004年 | 3770篇 |
2003年 | 3334篇 |
2002年 | 2298篇 |
2001年 | 2085篇 |
2000年 | 1804篇 |
1999年 | 1680篇 |
1998年 | 1382篇 |
1997年 | 1296篇 |
1996年 | 1245篇 |
1995年 | 1206篇 |
1994年 | 1022篇 |
1993年 | 918篇 |
1992年 | 827篇 |
1991年 | 643篇 |
1990年 | 593篇 |
1989年 | 497篇 |
1988年 | 495篇 |
1987年 | 444篇 |
1986年 | 386篇 |
1985年 | 504篇 |
1984年 | 415篇 |
1983年 | 256篇 |
1982年 | 338篇 |
1981年 | 305篇 |
1980年 | 248篇 |
1979年 | 205篇 |
1978年 | 128篇 |
1977年 | 101篇 |
1976年 | 85篇 |
1975年 | 39篇 |
排序方式: 共有10000条查询结果,搜索用时 950 毫秒
991.
Carlo Cervia Jakob Nilsson Yves Zurbuchen Alan Valaperti Jens Schreiner Aline Wolfensberger Miro E. Raeber Sarah Adamo Sebastian Weigang Marc Emmenegger Sara Hasler Philipp P. Bosshard Elena De Cecco Esther Bächli Alain Rudiger Melina Stüssi-Helbling Lars C. Huber Annelies S. Zinkernagel Onur Boyman 《The Journal of allergy and clinical immunology》2021,147(2):545-557.e9
992.
Mechanisms dependent on tryptophan catabolism regulate immune responses in primary Sjögren's syndrome 下载免费PDF全文
Pertovaara M Raitala A Uusitalo H Pukander J Helin H Oja SS Hurme M 《Clinical and experimental immunology》2005,142(1):155-161
To investigate the possible role of tryptophan metabolism in immune regulation of primary Sjögren's syndrome (pSS) the serum concentrations of tryptophan and its metabolite kynurenine were measured by reverse‐phase high‐performance liquid chromatography (HPLC) in 103 patients with pSS, 56 patients with sicca symptoms and 309 healthy blood donors. The kynurenine per tryptophan ratio (kyn/trp), which reflects the activity of the indoleamine‐pyrrole 2,3‐dioxygenase (IDO) enzyme involved in tryptophan catabolism, was calculated. Both female and male patients with pSS had significantly higher serum kynurenine concentrations and kyn/trp than subjects with sicca symptoms or healthy blood donors. The median (quartile range) concentration of kynurenine in female patients with pSS was 2·41 µmol/l (1·86–3·26) compared with 1·85 µmol/l (1·58–2·38, P < 0·0001) in subjects with sicca symptoms and 1·96 µmol/l (1·65–2·27, P < 0·0001) in healthy blood donors. Their kyn/trp × 1000 was 34·0 (25·1–44·3) compared with 25·3 (21·1–31·5, P < 0·0001) in subjects with sicca symptoms and 24·3 (21·0–28·9, P < 0·0001) in healthy blood donors. Female pSS patients with high IDO activity (kyn/trp × 1000 ≥ 34·0) had significantly higher ESR, serum C‐reactive protein, serum IgA and serum beta‐2 microglobulin concentrations as well as higher serum creatinine levels, and they had positive antinuclear antibodies more frequently and presented with more American‐European consensus group criteria than those with low IDO activity (kyn/trp × 1000 < 34·0). These data suggest that mechanisms dependent on tryptophan catabolism regulate immune responses in pSS. Tryptophan degradation is enhanced in patients with pSS, and high IDO activity is associated with severity of pSS. 相似文献
993.
This report details the fine-needle aspiration biopsy (FNAB) cytomorphologic features of two cases of salivary gland mycosis. Both patients had acquired immunodeficiency syndrome (AIDS) and presented with parotid gland masses. The first patient had Histoplasmosis with secondary infection by Candida. Cytopathologically, the FNAB smears showed classic features of a deep-seated mycosis characterized by necrosis and scattered fungal forms. The second patient had a colonizing sialadenitis caused by either Asperigillus or Fusarium. Cytopathologically, the findings were similar to those seen in aspergillomas of the lung orparanasal sinuses with numerous hyphal forms and an absence of an inflammatory response. Because mycotic disease can induce a wide spectrum of pathogenic change, other benign or malignant, solid or cystic lesions enter into the differential diagnosis. Diagn Cytopathol 1994; 11:286–290. © 1994 Wiley-Liss, Inc. 相似文献
994.
Mutations in the human fibrillin 1 gene (FBN1) cause the Marfan syndrome (MFS), an autosomal dominant connective tissue disorder. Knowledge about FBN1 mutations is important for early diagnosis, management, and genetic counseling. However, mutation detection in FBN1 is a challenge because the gene is very large in size ( approximately 200 kb) and the approximately 350 mutations detected so far are scattered over 65 exons. Conventional methods for large-scale detection of mutations are expensive, technically demanding, or time consuming. Recently, a high-capacity low-cost mutation detection method was introduced based on denaturing high-performance liquid chromatography (DHPLC). To assess the sensitivity and specificity of this method, we blindly screened 64 DNA samples of known FBN1 genotype exon-by-exon using exon-specific DHPLC conditions. Analysis of 682 PCR amplicons correctly identified 62 out of 64 known sequence variants. In three MFS patients of unknown FBN1 genotype, we detected two mutations and eight polymorphisms. Overall, 20 mutations and two polymorphisms are described here for the first time. Our results demonstrate 1) that DHPLC is a highly sensitive (89-99%, P = 0.05) method for FBN1 mutation detection; but 2) that chromatograms with moderate and weak pattern abnormalities also show false positive signals (in all 45-59%, P = 0.05); 3) that the difference in the chromatograms of heterozygous and homozygous amplicons is mostly independent of the type of sequence change; and 4) that DHPLC column conditions, additional base changes, and the amounts of injected PCR products influence significantly the shape of chromatograms. A strategy for FBN1 mutation screening is discussed. 相似文献
995.
本文通过对小鼠急性毒性实验,抗炎实验,对胸腺脾脏的影响及对豚鼠在体、离体气管平滑肌作用实验,观察了郃郎喘必消冲剂的药理学效应。结果表明,该制剂无明显毒性,最大耐受量为1000g/kg/d。它有明显的对抗二甲苯致小鼠耳炎及延长组胺诱发哮喘发作潜伏期的作用,对豚鼠离体气管平滑肌无松驰作用,对小鼠胸腺和脾脏有使其重量减小的趋势,但与对照组比较无显著性差异。 相似文献
996.
997.
George Capone Mary Stephens Stephanie Santoro Brian Chicoine Peter Bulova Moya Peterson Joan Jasien Anna Jo Smith Down Syndrome Medical Interest Group Adult Health Workgroup 《American journal of medical genetics. Part A》2020,182(7):1832-1845
Adults with Down syndrome (DS) represent a unique population who are in need of clinical guidelines to address their medical care. Many of these conditions are of public health importance with the potential to develop screening recommendations to improve clinical care for this population. Our workgroup previously identified and prioritized co‐occurring medical conditions in adults with DS. In this study, we again performed detailed literature searches on an additional six medical conditions of clinical importance. A series of key questions (KQ) were formulated a priori to guide the literature search strategy. Our KQs focused on disease prevalence, severity, risk‐factors, methodologies for screening/evaluation, impact on morbidity, and potential costs/benefits. The available evidence was extracted, evaluated and graded on quality. The number of participants and the design of clinical studies varied by condition and were often inadequate for answering most of the KQ. Based upon our review, we provide a summary of the findings on hip dysplasia, menopause, acquired cardiac valve disease, type 2 diabetes mellitus, hematologic disorders, and dysphagia. Minimal evidence demonstrates significant gaps in our clinical knowledge that compromises clinical decision‐making and management of these medically complex individuals. The creation of evidence‐based clinical guidance for this population will not be possible until these gaps are addressed. 相似文献
998.
Takeki Tsutsui Yuriko Tanaka Yuko Matsudo J. Carl Barrett 《Methods in Cell Science》1995,17(2):155-160
Immortalization of normal human fibroblasts is a very rare event. Multiple genes such as p53 and cellular senescence genes are possibly involved in immortalization of human fibroblasts, suggesting that multiple treatments with carcinogens are required for the immortalization. We describe here the procedure for immortalization of human fibroblasts (MDAH 087) from Li-Fraumeni cancer syndrome with a germ-line p53 mutation. The cells were subjected to multiple treatments with aflatoxin B1 (AFB1) in the presence of exogenous metabolic activation with rat liver post-mitochondrial supernatant (PMS), and 3 of 9 MDAH 087 cell cultures treated 1–3 times with 0.1–1 µg/ml AFB1 became immortal, defined as continuous growth for over 300 population doublings after the first treatment. However, cultures of human fibroblasts from a normal embryo treated under the same conditions failed to escape senescence. The results indicate that the model of human fibroblasts with a mutated p53 allele exposed to AFB1 is potentially useful for studying mechanisms of chemically induced immortalization. 相似文献
999.
Hiroki Kurahashi Kenzo Akagi Ikuo Yana Thomas Melot Olivier Delattre Gilles Thomas Shintaro Okada Shin-ichiro Takai Isamu Nishisho 《Journal of human genetics》1994,39(2):243-248
Summary Eight cosmid clones were regionally assigned to small subregions of chromosome 22 by hybridization with a total of 22 somatic cell hybrids. One cosmid was localized to the proximal part of 22q which contained the region commonly deleted in the DiGeorge syndrome. Seven cosmids showing restriction fragment length polymorphisms were localized to the telomeric region distal to the MB locus, which was reported to be frequently deleted in sporadic meningioma. These cosmids, when finely mapped and ordered, are considered useful for the identification of genetic alterations on this chromosome arm. 相似文献
1000.
Marfan syndrome: exclusion of genetic linkage to the COL1A2 gene 总被引:11,自引:0,他引:11
Marfan Syndrome is a genetic disorder of the connective tissue. Individuals from one large family with this disorder were genotyped for COL1A2 gene associated RFLPs. Our results demonstrated that the COL1A2 gene, encoding the proa2(I) collagen chain, segregated independently of the phenotype and it is therefore excluded as the mutant locus in this family. 相似文献