全文获取类型
收费全文 | 16390篇 |
免费 | 1250篇 |
国内免费 | 39篇 |
专业分类
耳鼻咽喉 | 141篇 |
儿科学 | 551篇 |
妇产科学 | 543篇 |
基础医学 | 2125篇 |
口腔科学 | 217篇 |
临床医学 | 2120篇 |
内科学 | 2970篇 |
皮肤病学 | 351篇 |
神经病学 | 1986篇 |
特种医学 | 346篇 |
外国民族医学 | 22篇 |
外科学 | 1586篇 |
综合类 | 134篇 |
一般理论 | 23篇 |
预防医学 | 2092篇 |
眼科学 | 142篇 |
药学 | 1096篇 |
中国医学 | 30篇 |
肿瘤学 | 1204篇 |
出版年
2024年 | 36篇 |
2023年 | 213篇 |
2022年 | 385篇 |
2021年 | 741篇 |
2020年 | 472篇 |
2019年 | 708篇 |
2018年 | 729篇 |
2017年 | 499篇 |
2016年 | 534篇 |
2015年 | 610篇 |
2014年 | 804篇 |
2013年 | 975篇 |
2012年 | 1456篇 |
2011年 | 1407篇 |
2010年 | 761篇 |
2009年 | 610篇 |
2008年 | 988篇 |
2007年 | 895篇 |
2006年 | 808篇 |
2005年 | 741篇 |
2004年 | 647篇 |
2003年 | 495篇 |
2002年 | 418篇 |
2001年 | 133篇 |
2000年 | 123篇 |
1999年 | 132篇 |
1998年 | 88篇 |
1997年 | 63篇 |
1996年 | 54篇 |
1995年 | 43篇 |
1994年 | 37篇 |
1993年 | 41篇 |
1992年 | 83篇 |
1991年 | 68篇 |
1990年 | 70篇 |
1989年 | 70篇 |
1988年 | 57篇 |
1987年 | 44篇 |
1986年 | 60篇 |
1985年 | 50篇 |
1984年 | 39篇 |
1983年 | 26篇 |
1979年 | 26篇 |
1978年 | 31篇 |
1976年 | 29篇 |
1975年 | 24篇 |
1971年 | 26篇 |
1970年 | 36篇 |
1969年 | 26篇 |
1968年 | 24篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Kitty Pavlakis Panteleimon Kountourakis Efstathios Stathopoulos Amanda Psyrri Dimitra Rontogianni Maria Kafousi Maria Derivianaki Nikolaos Xiros Dimitrios Pectasides Theofanis Economopoulos 《Applied immunohistochemistry & molecular morphology》2007,15(4):441-445
This study was sought to evaluate the relationship between Her-2 protein expression, cellular localization, gene amplification, and other clinicopathologic parameters in colorectal carcinomas. Her-2 protein expression and gene amplification were assessed in paraffin sections from 106 primary colorectal adenocarcinoma cases using immunohistochemistry and fluorescence in situ hybridization. Both membranous and cytoplasmic immunostaining was evaluated. The results were correlated with each other and with tumor grade, stage, and overall survival. Membranous and cytoplasmic protein expression was identified in 6 (5.6%) and 13 (12.26%) cases, respectively. Gene amplification was detected in 4 (3.7%) cases. There was a high concordance between membranous protein expression and gene amplification (kappa=0.791). No apparent association with any of the clinicopathologic parameters was identified. Membranous Her-2 protein expression and gene amplification are encountered in a small subset of colorectal carcinomas and are highly concordant events. Cytoplasmic protein expression might be either artifactual or it might represent a cross-reacting protein or a precursor form of the mature protein. 相似文献
62.
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
63.
作者于2004年在指导学生对一具90岁男性尸体标本进行解剖时,见其左前臂桡侧腕伸肌区存在有桡侧腕伸副肌(extensor carpi radialis accessorius,ECRA)合并桡侧腕长、短伸肌之间出现两条副肌腱并相互交叉连接的一种罕见的复合变异。 相似文献
64.
Miksch S Lumsden A Guenther UP Foernzler D Christen-Zäch S Daugherty C Ramesar RK Lebwohl M Hohl D Neldner KH Lindpaintner K Richards RI Struk B 《Human mutation》2005,26(3):235-248
Pseudoxanthoma elasticum (PXE) is a systemic heritable disorder that affects the elastic tissue in the skin, eye, and cardiovascular system. Mutations in the ABCC6 gene cause PXE. We performed a mutation screen in ABCC6 using haplotype analysis in conjunction with direct sequencing to achieve a mutation detection rate of 97%. This screen consisted of 170 PXE chromosomes in 81 families, and detected 59 distinct mutations (32 missense, eight nonsense, and six likely splice-site point mutations; one small insertion; and seven small and five large deletions). Forty-three of these mutations are novel variants, which increases the total number of PXE mutations to 121. While most mutations are rare, three nonsense mutations, a splice donor site mutation, and the large deletion comprising exons 23-29 (c.2996_4208del) were identified as relatively frequent PXE mutations at 26%, 5%, 3.5%, 3%, and 11%, respectively. Chromosomal haplotyping with two proximal and two distal polymorphic markers flanking ABCC6 demonstrated that most chromosomes that carry these relatively frequent PXE mutations have related haplotypes specific for these mutations, which suggests that these chromosomes originate from single founder mutations. The types of mutations found support loss-of-function as the molecular mechanism for the PXE phenotype. In 76 of the 81 families, the affected individuals were either homozygous for the same mutation or compound heterozygous for two mutations. In the remaining five families with one uncovered mutation, affected showed allelic compound heterozygosity for the cosegregating PXE haplotype. This demonstrates pseudo-dominance as the relevant inheritance mechanism, since disease transmission to the next generation always requires one mutant allelic variant from each parent. In contrast to other previous clinical and molecular claims, our results show evidence only for recessive PXE. This has profound consequences for the genetic counseling of families with PXE. 相似文献
65.
Amanda Hall Anthony Hayes Liesbeth Brown Ross Tubo Bruce Caterson 《International journal of experimental pathology》2004,85(4):A63-A64
Introduction The aims of the current study were to (i) tissue engineer a cartilage graft with structural and biochemical properties of native articular cartilage in vivo, with potential for use in cartilage repair technologies and (ii) utilize this model as a test system to evaluate the efficiency of novel therapeutics for future research into cartilage metabolism in health and disease. Materials and methods Articular cartilage was harvested from hock joints of (young) 7‐day and (old) 18‐month bovine sources. Cells were isolated by enzymatic digestion and seeded at a range of cell densities (2, 4, 6, 8, 10 and 12 × 106 cells/insert) into type II collagen‐coated Millipore filter inserts and cultured as described previously ( Kandel et al. 1995 ). In order to mimic a catabolic effect on cartilage, some samples were treated with IL‐1α (10 ng/ml) for 24 h in the absence or presence of experimental drugs. Proteoglycan (PG) release, detectable in the medium, was analysed by colorimetric assay ( Farndale et al. 1986 ). At the end of the culture period, cartilage grafts were fixed, sectioned and stained with Alcian Blue or immuno‐fluorescently labelled with a panel of monoclonal antibodies recognizing several components of the graft extracellular matrix. Results Full‐depth chondrocytes from both young and old bovine sources produced a stratified hyaline tissue with distinct zones after 2 weeks in culture. These zones approximated to the surface, middle and deep zones that characterize native articular cartilage in vivo. Increased culture time and seeding density produced cartilage of an increased thickness and cellularity, respectively. Grafts produced from young cartilage contained approximately 3 times more sulfated PG than grafts produced from an old cartilage, indicating an increased matrix secretion in these cultures. Histologically, the old grafts were also thinner and more weakly stained with Alcian Blue, indicating a lower sulfated PG content. Addition of IL‐1α to the cultures resulted in a dramatic PG release from the cartilage grafts, manifest histologically as a loss of Alcian Blue staining in the upper third of the cartilage tissue. Immunofluorescent staining identified subtle changes in matrix composition and in the structure and catabolism of matrix proteoglycans in response to both IL‐1a and the experimental drugs tested. Discussion The grafts produced had many structural and biochemical similarities to articular cartilage in vivo. These grafts may better integrate with the host cartilage in cartilage repair procedure. This culture system also provides ideal conditions to analyse the response of engineered grafts to catabolic factors that occur in the arthritic joint, along with ideal conditions for research into drug therapies. Advantages of this culture system, in comparison with an explant system, are that effects can be analysed within a 24‐h period. Future work will include applying fatty acids, modified glucosamine and some Asian herbal remedies to this culture system and analysing their potential chondroprotective effects. 相似文献
66.
Amanda B. Spurdle Sara Shankman Michele Ramsay 《American journal of medical genetics. Part A》1995,55(1):53-56
A molecular investigation of 16 Bantu-speaking Black XX true hermaphrodites was undertaken in an attempt to determine the cause of the disorder. Y-specific sequences, including sequences mapping to the sexdetermining region of the Y, were shown to be absent from lymphocyte tissue of all 16 patients tested. Y chromosome sequences were also absent from the ovarian and testicular components of both ovotestes of a single XX true hermaphrodite, thus excluding gonadal mosaicism involving Y chromosome sequences. Since there is evidence for Xp genes involved in testis determination/differentiation, uniparental disomy of the X chromosome was investigated in 14 XXTH families. Uniparental disomy was excluded in 12 of the 14 families, and isodisomy was excluded in the remaining two cases. © 1995 Wiley-Liss, Inc. 相似文献
67.
Two-pore (2P)-domain K+ channels have been shown recently to play a critical role in both cell apoptosis and tumorigenesis. The activity of two-pore, (TWIK)-related acid-sensitive-3 (TASK-3) K+ channels, is responsible for K+-dependent apoptosis of cultured cerebellar granule neurons. Neuron death can be prevented by conditions that specifically reduce K+ efflux through the TASK-3 channels. Moreover, genetic transfer of TASK subunits into hippocampal neurons that lack TASK-3, induces apoptosis. These results indicate a direct link between TASK K+ channel activity and the physiological process of programmed cell death. The TASK-3 K+ channel gene has also been shown to be amplified genomically and over-expressed in a significant number of breast tumours. TASK-3 has a potent oncogenic potential that appears to be related directly to its K+ channel function. In the present review, we will examine the pro-apoptotic and oncogenic properties of TASK-3. We will discuss: (1) the molecular and functional properties of the novel family of mammalian 2P domain K+ channels; (2) the role of TASK-3 in cerebellar granule neuron apoptosis and (3) the role of TASK-3 in breast tumorigenesis. 相似文献
68.
Jevitt LA Smith AJ Williams PP Raney PM McGowan JE Tenover FC 《Microbial drug resistance (Larchmont, N.Y.)》2003,9(4):389-393
We assessed the in vitro activities of daptomycin, linezolid, and quinupristin-dalfopristin (QD) against a contemporary challenge panel of 88 staphylococcal and 90 enterococcal isolates. The staphylococci selected included vancomycin-intermediate Staphylococcus aureus (VISA), methicillin-resistant S. aureus, and coagulasenegative staphylococci. Enterococcal isolates included vancomycin-resistant Enterococcus faecium (VREF) containing either vanA, vanB1, or vanD. The MICs of daptomycin, linezolid, and QD were determined using commercial broth microdilution panels. All three VISA isolates were susceptible to daptomycin, linezolid, and QD. QD was the most active agent against staphylococcal isolates (MIC50 < or = 0.5 microg/ml and MIC90 = 1 microg/ml), including those with decreased susceptibility to vancomycin. QD was also the most active agent against VREF (MIC90 < or = 0.5 microg/ml). No differences were seen for susceptibility of vanA, vanB1, and vanD VREF strains for daptomycin, linezolid, or QD. Daptomycin was the most effective against E. faecalis. On the basis of manufacturer-suggested interpretive criteria, 92% of isolates were susceptible (MIC90 = 4 microg/ml). All isolates tested were susceptible to at least one antimicrobial agent for which interpretive criteria have been defined. Population analysis of three S. aureus isolates for which the daptomycin MICs were 8 microg/ml showed a pattern of homogeneous resistance. 相似文献
69.
Lopes Amanda Forster Machado Thais Costa Nascimento Viviane Gabriela Bertoli Ciro João Leone Claudio 《Maternal and child health journal》2022,26(6):1305-1311
Maternal and Child Health Journal - To study the relationship between cesarean Delivery (CD) and overweight in preschool children, considering the presence of birth aspects and demographic... 相似文献
70.
Roberts Amanda Jellicoe Mark Fox Kathryn 《Advances in health sciences education : theory and practice》2022,27(1):7-21
Advances in Health Sciences Education - Feedback uptake relies on interactions between learners and educators Winstone (Educ Psychol 52: 17–37, 2017). Feedback that coaches using a... 相似文献