全文获取类型
收费全文 | 38864篇 |
免费 | 2544篇 |
国内免费 | 97篇 |
专业分类
耳鼻咽喉 | 448篇 |
儿科学 | 1435篇 |
妇产科学 | 946篇 |
基础医学 | 4787篇 |
口腔科学 | 462篇 |
临床医学 | 6456篇 |
内科学 | 6744篇 |
皮肤病学 | 401篇 |
神经病学 | 3740篇 |
特种医学 | 800篇 |
外国民族医学 | 1篇 |
外科学 | 3578篇 |
综合类 | 362篇 |
一般理论 | 49篇 |
预防医学 | 5508篇 |
眼科学 | 403篇 |
药学 | 2365篇 |
中国医学 | 44篇 |
肿瘤学 | 2976篇 |
出版年
2024年 | 30篇 |
2023年 | 324篇 |
2022年 | 449篇 |
2021年 | 848篇 |
2020年 | 602篇 |
2019年 | 939篇 |
2018年 | 1094篇 |
2017年 | 812篇 |
2016年 | 852篇 |
2015年 | 946篇 |
2014年 | 1328篇 |
2013年 | 2098篇 |
2012年 | 3038篇 |
2011年 | 3214篇 |
2010年 | 1714篇 |
2009年 | 1553篇 |
2008年 | 2785篇 |
2007年 | 2794篇 |
2006年 | 2737篇 |
2005年 | 2687篇 |
2004年 | 2476篇 |
2003年 | 2199篇 |
2002年 | 2110篇 |
2001年 | 240篇 |
2000年 | 207篇 |
1999年 | 279篇 |
1998年 | 434篇 |
1997年 | 341篇 |
1996年 | 260篇 |
1995年 | 211篇 |
1994年 | 220篇 |
1993年 | 214篇 |
1992年 | 129篇 |
1991年 | 122篇 |
1990年 | 94篇 |
1989年 | 104篇 |
1988年 | 95篇 |
1987年 | 81篇 |
1986年 | 89篇 |
1985年 | 86篇 |
1984年 | 101篇 |
1983年 | 79篇 |
1982年 | 91篇 |
1981年 | 100篇 |
1980年 | 71篇 |
1979年 | 42篇 |
1978年 | 31篇 |
1977年 | 38篇 |
1976年 | 21篇 |
1975年 | 24篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
Amanda E. Brandon Amanda C. Boyce Eugenie R. Lumbers Monika A. Zimanyi John F. Bertram Karen J. Gibson 《Anatomical record (Hoboken, N.J. : 2007)》2008,291(3):318-324
We have shown that fetuses whose mothers underwent subtotal nephrectomy (STNx) before pregnancy had high urine flow rates and sodium excretions, but lower hematocrits, plasma chloride, and plasma renin levels compared with controls. To see if these functional differences in utero persist after birth and are the result of altered renal development, we studied 8 lambs born to STNx mothers (STNxL) and 10 controls (ConL) in the second week of life. These lambs were of similar body weights, nose–rump lengths and abdominal girths. Their kidney weights were not different (ConL 36.1 ± 1.9 vs. STNxL 39.8 ± 3.3 g), nor were kidney dimensions or glomerular number (ConL 423,520 ± 22,194 vs. STNxL 429,530 ± 27,471 glomeruli). However, STNxL had 30% larger glomerular volumes (both mean and total, P < 0.01) and there was a positive relationship between total glomerular volume and urinary protein excretion (P < 0.05) in STNxL. Despite this change in glomerular morphology, glomerular filtration rate, tubular function, urine flow, and sodium excretion rates were not different between STNxL and ConL, nor were plasma electrolytes, osmolality, and plasma renin levels. Thus while many of the functional differences seen in late gestation were not present at 1–2 weeks after birth, the alteration in glomerular size and its relationship to protein excretion suggests that exposure to this altered intrauterine environment may predispose offspring of mothers with renal dysfunction to renal disease in adult life. Anat Rec, 291:318–324, 2008. © 2008 Wiley‐Liss, Inc. 相似文献
132.
133.
Dixon J Ellis I Bottani A Temple K Dixon MJ 《American journal of medical genetics. Part A》2004,(3):244-248
Treacher Collins syndrome (TCS) is an autosomal dominant disorder of facial development, which results from mutations in TCOF1. TCS comprises conductive hearing loss, hypoplasia of the mandible and maxilla, downward sloping palpebral fissures and cleft palate. Although, there is usually a reasonable degree of bilateral symmetry, a high degree of both inter- and intrafamilial variability is characteristic of TCS. The wide variation in the clinical presentation of different patients, together with the fact that more than 60% of cases arise de novo, can complicate the diagnosis of mild cases and genetic counselling. In the current study, we describe how molecular techniques have been used to facilitate pre- and postnatal disease diagnoses in 13 TCS families. 相似文献
134.
ALK expression in extranodal anaplastic large cell lymphoma favours systemic disease with (primary) nodal involvement and a good prognosis and occurs before dissemination 总被引:3,自引:0,他引:3 下载免费PDF全文
ten Berge RL Oudejans JJ Ossenkoppele GJ Pulford K Willemze R Falini B Chott A Meijer CJ 《Journal of clinical pathology》2000,53(6):445-450
AIMS: In anaplastic large cell lymphoma (ALCL), the site of origin has been described as an important prognostic factor. Recently, a fusion protein containing anaplastic lymphoma kinase (ALK) was described in systemic nodal ALCL, and shown to be associated with a good prognosis. The aims of this study were to investigate whether the presence of ALK protein differs between ALCL of different sites of origin; to determine whether ALK expression occurs before dissemination to other sites; and, finally, to investigate whether the site of origin remains a prognostic parameter in ALK negative ALCL. METHODS: ALK expression, as detected by immunohistochemistry using the monoclonal antibodies ALK1 and ALKc, was studied in 85 ALCLs from different sites of origin. In 22 patients, ALK expression was studied in multiple biopsies from different sites (including 13 skin, 16 lymph node, and nine other). Overall survival time was analysed using the Kaplan Meier method. RESULTS: ALK expression was found in 20 of 51 systemic ALCLs with (primary) nodal involvement. No ALK expression was found in 15 primary cutaneous, 14 gastrointestinal, and five nasal ALCLs. Multiple and subsequent biopsies of patients showed ALK expression to be identical to that seen in the primary diagnostic biopsy. Kaplan Meier survival curves showed that in ALK negative ALCLs originating from different sites, primary cutaneous cases are associated with an excellent overall survival, whereas the other cases show a comparable five years survival of less than 40%. CONCLUSIONS: If present, ALK expression favours systemic ALCL with (primary) nodal involvement, and can be used in differentiating between extranodal involvement of systemic (nodal) ALCL and primary extranodal ALCL. ALK is expressed consistently in multiple biopsies of a given patient, indicating that the chromosomal abnormality leading to aberrant ALK expression occurs before dissemination to other sites. Finally, in ALK negative non-cutaneous ALCLs, different sites of origin show comparable poor survival. 相似文献
135.
Sperm analysis by FISH in a case of t(17; 22) (q11; q12) balanced translocation: case report 总被引:2,自引:0,他引:2
Geneix A Schubert B Force A Rodet K Briançon G Boucher D 《Human reproduction (Oxford, England)》2002,17(2):325-331
Individual sperm from men with balanced translocations have different chromosomal contents. Thus, an estimation of the overall sperm chromosomal imbalance of such patients could help to give the couple an adapted genetic counselling. We report here the study of a balanced translocation carrier, t(17;22) (q11;q12) whose reproductive history reported four miscarriages. Moreover, he had an abnormal semen analysis with oligoteratozoospermia. The meiotic segregation pattern was examined in 700 sperm, using fluorescence in-situ hybridization (FISH). Nineteen percent of the sperm had balanced translocations or were normal. All other sperm were unbalanced (81%) and their distribution was observed as follows: the frequencies of adjacent 1, adjacent 2 and 3:1 segregations were 12.9, 5.8 and 46.8% respectively. Among the segregations scored, 13.7% were related to second meiotic division abnormalities. Less than 2% of the total sperm scored were not explained. The 3:1 segregation was present at a very high rate, which is very unusual. In cases of balanced translocations, we believe that no general features can be drawn. Thus, the FISH technique may be very helpful for genetic counselling, which remains an important step and must be done with care. 相似文献
136.
Rita Machaalani Jane L Radford Karen A Waters 《Applied immunohistochemistry & molecular morphology》2007,15(4):463-470
Fixation methods for tissue often vary amongst clinical and research laboratories. To evaluate the effects of fixation method on studies of brain tissue, we examined immunohistochemical outcomes amongst 2 fixatives, 4 caspase-3 antibodies, and 2 species (human infants and piglets). Fixatives were 10% neutral buffered formalin (NBF) or 10% NBF and glacial acetic acid (FAA). Antibodies for caspase-3 were commercially obtained and included 2 for active caspase-3, and 2 for procaspase-3 (CASP3 and CPP32). Immunohistochemical staining of caspase-3 varied with fixation method, with the greatest effect of fixation method observed for the active caspase-3 antibodies and this effect was present in both species. In NBF-fixed tissue, active caspase-3 immunoreactivity was only visible microscopically, and was specific to neuronal cell bodies. In FAA-fixed tissue, active caspase-3 immunoreactivity was visible macroscopically, and predominantly present in fiber tracts and fasciculi compared with neuronal bodies. Fixation and species differences were also identified for the procaspase-3 antibodies, CASP3 and CPP32, where FAA-fixed pig tissue showed abundant staining of blood vessels that were not observed in the NBF-fixed pig tissue or in the human tissue. This study characterizes differences in immunohistochemical outcomes using commercially available antibodies for caspase-3, according to tissue fixation method and species. 相似文献
137.
Berriman M Hall N Sheader K Bringaud F Tiwari B Isobe T Bowman S Corton C Clark L Cross GA Hoek M Zanders T Berberof M Borst P Rudenko G 《Molecular and biochemical parasitology》2002,122(2):131-140
Trypanosoma brucei evades the immune system by switching between Variant Surface Glycoprotein (VSG) genes. The active VSG gene is transcribed in one of approximately 20 telomeric expression sites (ESs). It has been postulated that ES polymorphism plays a role in host adaptation. To gain more insight into ES architecture, we have determined the complete sequence of Bacterial Artificial Chromosomes (BACs) containing DNA from three ESs and their flanking regions. There was variation in the order and number of ES-associated genes (ESAGs). ESAGs 6 and 7, encoding transferrin receptor subunits, are the only ESAGs with functional copies in every ES that has been sequenced until now. A BAC clone containing the VO2 ES sequences comprised approximately half of a 330 kb 'intermediate' chromosome. The extensive similarity between this intermediate chromosome and the left telomere of T. brucei 927 chromosome I, suggests that this previously uncharacterised intermediate size class of chromosomes could have arisen from breakage of megabase chromosomes. Unexpected conservation of sequences, including pseudogenes, indicates that the multiple ESs could have arisen through a relatively recent amplification of a single ES. 相似文献
138.
Inge Van de Walle Karen Silence Kevin Budding Liesbeth Van de Ven Kim Dijkxhoorn Elisabeth de Zeeuw Cafer Yildiz Sofie Gabriels Jean-Michel Percier Johanna Wildemann Jan Meeldijk Peter J. Simons Louis Boon Linda Cox Rob Holgate Rolf Urbanus Henny G. Otten Jeanette H.W. Leusen Peter Boross 《The Journal of allergy and clinical immunology》2021,147(4):1420-1429.e7
139.
While both murine and human homologues of the LSP1 gene (lymphocyte-specific gene 1) and its protein products have been identified, studies on human LSP1 have been limited. The present report describes a detailed immunocytochemical study of the distribution and localization of human LSP1 in both normal and neoplastic cells and tissues. The specificity of the monoclonal anti-LSP1 reagent was confirmed by expression cloning and transfection studies. The intracellular 60 000 MW LSP1 protein was found to be present in peripheral blood B cells, monocytes and granulocytes but absent in a subpopulation of circulating T cells (10-15% of CD3-positive T cells). The presence of LSP1 protein in medullary thymocytes, but only in scattered cortical thymocytes, provided additional evidence for heterogeneity of expression in T cells. Novel observations also included the presence of LSP1 in plasma cells, dendritic cells and Langerhans' cells. The leucocyte-restricted distribution of LSP1 protein means that it may play an important role in haematopathology. LSP1 protein was detected in a wide range of leukaemias and lymphomas, particularly of B-cell origin, and in tumour cells in classical Hodgkin's disease. Of interest was the indication of a reciprocal relationship in the expression of LSP1 and ALK (anaplastic lymphoma kinase) proteins in patients with anaplastic large cell lymphoma. As the anti-LSP1 reagent used in the present study recognizes a formalin-resistant epitope it should be of considerable value in the diagnosis of routinely fixed material. 相似文献
140.
Congenital cytomegalovirus (CMV) infection and hearing deficit. 总被引:20,自引:0,他引:20