全文获取类型
收费全文 | 5214篇 |
免费 | 490篇 |
国内免费 | 42篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 200篇 |
妇产科学 | 87篇 |
基础医学 | 737篇 |
口腔科学 | 132篇 |
临床医学 | 491篇 |
内科学 | 865篇 |
皮肤病学 | 65篇 |
神经病学 | 377篇 |
特种医学 | 381篇 |
外科学 | 837篇 |
综合类 | 144篇 |
一般理论 | 31篇 |
预防医学 | 393篇 |
眼科学 | 76篇 |
药学 | 554篇 |
中国医学 | 11篇 |
肿瘤学 | 350篇 |
出版年
2022年 | 28篇 |
2021年 | 82篇 |
2020年 | 43篇 |
2019年 | 74篇 |
2018年 | 89篇 |
2017年 | 58篇 |
2016年 | 70篇 |
2015年 | 91篇 |
2014年 | 110篇 |
2013年 | 178篇 |
2012年 | 227篇 |
2011年 | 214篇 |
2010年 | 160篇 |
2009年 | 146篇 |
2008年 | 185篇 |
2007年 | 194篇 |
2006年 | 238篇 |
2005年 | 235篇 |
2004年 | 218篇 |
2003年 | 179篇 |
2002年 | 186篇 |
2001年 | 195篇 |
2000年 | 200篇 |
1999年 | 181篇 |
1998年 | 107篇 |
1997年 | 105篇 |
1996年 | 96篇 |
1995年 | 81篇 |
1994年 | 94篇 |
1993年 | 86篇 |
1992年 | 133篇 |
1991年 | 126篇 |
1990年 | 102篇 |
1989年 | 99篇 |
1988年 | 135篇 |
1987年 | 84篇 |
1986年 | 80篇 |
1985年 | 89篇 |
1984年 | 50篇 |
1983年 | 42篇 |
1982年 | 39篇 |
1981年 | 28篇 |
1980年 | 39篇 |
1979年 | 59篇 |
1978年 | 45篇 |
1977年 | 50篇 |
1976年 | 50篇 |
1975年 | 37篇 |
1974年 | 32篇 |
1973年 | 43篇 |
排序方式: 共有5746条查询结果,搜索用时 343 毫秒
81.
Mutational analysis of the SOX9 gene in campomelic dysplasia and autosomal sex reversal: lack of genotype/phenotype correlations 总被引:9,自引:1,他引:9
Meyer J; Sudbeck P; Held M; Wagner T; Schmitz ML; Bricarelli FD; Eggermont E; Friedrich U; Haas OA; Kobelt A; Leroy JG; Van Maldergem L; Michel E; Mitulla B; Pfeiffer RA; Schinzel A; Schmidt H; Scherer G 《Human molecular genetics》1997,6(1):91-98
It has previously been shown that, in the heterozygous state, mutations in
the SOX9 gene cause campomelic dysplasia (CD) and the often associated
autosomal XY sex reversal. In 12 CD patients, 10 novel mutations and one
recurrent mutation were characterized in one SOX9 allele each, and in one
case, no mutation was found. Four missense mutations are all located within
the high mobility group (HMG) domain. They either reduce or abolish the
DNA-binding ability of the mutant SOX9 proteins. Among the five nonsense
and three frameshift mutations identified, two leave the C-terminal
transactivation (TA) domain encompassing residues 402-509 of SOX9 partly or
almost completely intact. When tested in cell transfection experiments, the
recurrent nonsense mutation Y440X, found in two patients who survived for
four and more than 9 years, respectively, exhibits some residual
transactivation ability. In contrast, a frameshift mutation extending the
protein by 70 residues at codon 507, found in a patient who died shortly
after birth, showed no transactivation. This is apparently due to
instability of the mutant SOX9 protein as demonstrated by Western blotting.
Amino acid substitutions and nonsense mutations are found in patients with
and without XY sex reversal, indicating that sex reversal in CD is subject
to variable penetrance. Finally, none of 18 female patients with XY gonadal
dysgenesis (Swyer syndrome) showed an altered SOX9 banding pattern in SSCP
assays, providing evidence that SOX9 mutations do not usually result in XY
sex reversal without skeletal malformations.
相似文献
82.
Primary total hip replacement (THR) surgery is the most commonly performed and successful reconstructive procedure in orthopaedic surgery. We performed a survey of Irish Orthopaedic consultants to elucidate current practices of primary THR in elderly and young patients and identify changing trends. There was an 83% response rate. Most respondents use a cemented THR in elderly patients. 69% use a different THR in younger patients compared to older patients. 9% refer younger patients to hip replacement specialist consultant colleagues. 70% report changing to a new implant or new technique in younger patients and 45% use a hybrid THR, 15% an uncemented THR, 15% perform hip resurfacing and 47% use different bearing surfaces. Only 17% use the Charnley hip prosthesis in younger patients. Young and active patients will place high demands on a new THR and newer techniques, implants and bearing surfaces are being adopted in the hope of better outcomes. 相似文献
83.
Aims : Synovial sarcomas are rare tumours occasionally arising in the pleural cavity, a site where their histological characteristics may be mistaken for those of malignant mesothelioma. We examined three cases of primary pleural synovial sarcoma in order to look for clinicopathological features that may help in distinguishing them from both mesotheliomas and other sarcomas that may arise in the pleura.
All three patients were male, aged 42, 28 and 42, respectively, and had no known exposure to asbestos. One biphasic tumour contained neutral mucin in focal epithelial elements that also stained positively for BerEP4 and AUA1. All three tumours showed focal positivity for either keratin or EMA in the sarcomatous elements, and they also stained positively for bcl-2 protein and MIC2 gene product (CD99).
Our results emphasize the importance of being aware of synovial sarcoma as a possible primary pleural malignancy, especially in a young patient with a localized mass. In addition, the presence of bcl-2 protein perhaps represents a useful marker in distinguishing synovial sarcoma, especially monophasic variants, from mesothelioma within a panel of antibodies. 相似文献
Methods and results
All three patients were male, aged 42, 28 and 42, respectively, and had no known exposure to asbestos. One biphasic tumour contained neutral mucin in focal epithelial elements that also stained positively for BerEP4 and AUA1. All three tumours showed focal positivity for either keratin or EMA in the sarcomatous elements, and they also stained positively for bcl-2 protein and MIC2 gene product (CD99).
Conclusions
Our results emphasize the importance of being aware of synovial sarcoma as a possible primary pleural malignancy, especially in a young patient with a localized mass. In addition, the presence of bcl-2 protein perhaps represents a useful marker in distinguishing synovial sarcoma, especially monophasic variants, from mesothelioma within a panel of antibodies. 相似文献
84.
Tate AR Foxall PJ Holmes E Moka D Spraul M Nicholson JK Lindon JC 《NMR in biomedicine》2000,13(2):64-71
The technique of magic angle spinning (MAS) high resolution (1)H NMR spectroscopy applied to intact tissues provides excellent peak resolution and thus much biochemical information. The use of computer-based pattern recognition techniques to classify human renal cortex tissue samples as normal or tumour based on their (1)H MAS NMR spectra has been investigated. In this preliminary study of 22 paired control and tumour samples, exploratory data analysis using principal components based on NMR spectral intensities showed clear separation of the two classes. Furthermore, using the supervised method of linear discriminant analysis, based on individual data point intensities or on integrated spectral regions, it was possible to distinguish between the normal and tumour kidney cortex tissue with 100% accuracy, including a single example of a metastatic tumour from a primary lung carcinoma. A tumour sample from the collecting duct of the kidney showed a different NMR spectral profile, and pattern recognition indicated that this sample did not classify with the cortical tumours. 相似文献
85.
Induction of epithelial-mesenchymal transition in alveolar epithelial cells by transforming growth factor-beta1: potential role in idiopathic pulmonary fibrosis 总被引:3,自引:0,他引:3
下载免费PDF全文
![点击此处可从《The American journal of pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Willis BC Liebler JM Luby-Phelps K Nicholson AG Crandall ED du Bois RM Borok Z 《The American journal of pathology》2005,166(5):1321-1332
86.
J F Levine D E Sonenshine W L Nicholson R T Turner 《Journal of medical entomology》1991,28(5):668-674
Ixodid ticks removed from hosts and from vegetation during March-November 1987 at sites in coastal Virginia and North Carolina were examined for Borrelia burgdorferi. B. burgdorferi was evident in nine (22%) Ixodes cookei Packard removed from rice rats (Oryzomys palustris), a white-footed mouse (Peromyscus leucopus), and raccoons (Procyon lotor); four (6%) Amblyomma americanum (L.) removed from raccoons; and two (3%) Dermacentor variabilis (Say) removed from a raccoon and a rice rat. B. burgdorferi was also detected in Ixodes dentatus Marx removed from a brown thrasher (Toxostoma rufum), a Carolina wren (Thryothoros ludovicianus), and a towhee (Piplio erythrophthalamus); and in Haemaphysalis leporispalustris (Packard) removed from a brown thrasher and a white-throated sparrow (Zonotrichia albicollis) netted at Kiptopeke Beach, Va. Two Ixodes dammini Spielman, Clifford, Piesman & Corwin were collected on Parramore Island; one specimen was examined for spirochetes, and it was infected with B. burgdorferi. No spirochetes were detected in host-seeking A. americanum and Amblyomma maculatum Koch removed from vegetation. The plasma of one P. leucopus and sera obtained from two P. lotor contained antibodies to B. burgdorferi. All infected ticks and the seroreactive hosts were collected from the Eastern Shore of Virginia. 相似文献
87.
Alloresponses to HLA-DP Detected in the Primary MLR: Correlation with a Single Amino Acid Difference
I Nicholson M Varney C Kanaan A Grigg J Szer K Tiedemann B.D Tait 《Human immunology》1997,55(2):163-169
The one-way mixed lymphocyte reaction (MLR-1) response was measured in both directions in 50 HLA-A, B, DR and DQ identical pairs and the role of DP studied in MLR stimulation. DR, DQ and DP typing was performed at the allele level by the polymerase chain reaction-sequence specific oligotyping (PCR-SSO) technique. The group consisted of 19 potential bone marrow transplant recipients and 34 matched unrelated donors. When more than one matched donor was available for a patient, donor/donor MLR-1 was also studied. DP identity was observed in 3 out of 50 pairs (6%), however due to homozygosity no incompatibility was present in the stimulating cells in 21 out of 100 cases (21%). There was a significant difference in the range of relative responses (RR) between zero DPB1 mismatches and one (p = 0.002) and two (p = 0.02) DPB1 mismatches: 52.4% of cases in the zero DPB1 mismatch group had RR < 1.0% compared with 31.6% and 27.3% in the one and two DPB1 mismatches. Stimulation by DPB1*0201 and 0301 gave the highest RR (12.9 ± 22.5 and 17.5 ± 17.0, respectively) while stimulation with DPB1*0401 and 0402 resulted in low levels of T cell response (1.3 ± 8.2 and 0.6 ± 11.5, respectively). When the responses were restricted to DPB1*0401 homozygotes to standardise for responder type similar results were obtained (DPB1*0201 v DPB1*0402 p = 0.008). The protein products of the DPB1*0201 and 0402 alleles differ by a single amino acid at position 69 (DPB1*0402—Lysine, DPB1*0201—glutamic acid). A further analysis was performed therefore scoring responders and stimulators as glutamic acid positive (E+) or negative (E−). There was a highly significant increase in the response to E+ stimulators compared with E− stimulators (p = 0.004). There was also a significant difference in the distribution of relative responses between the E+ stimulator group and the subgroups of E− responders/E− stimulators (p = 0.012) and E+ responders/E− stimulators (p = 0.009). However the amino acid difference at position 69 does not explain all responses due to DP in the MLR-1 as evidenced by the strong responses observed in cases where DPB1*0301 (lysine pos.) was the only difference on the stimulator cells. The results indicate that not all DP incompatibilities elicit a measurable T cell MLR response, but where a response does occur residue 69 in the first domain of DP appears to be pivotal. These results may have implications with respect to GVHD in bone marrow transplantation. 相似文献
88.
Timothy R.J. Nicholson Jian Yang Lynn E. DeLisi Timothy J. Crow 《American journal of medical genetics. Part A》2002,114(6):637-640
A case (based upon an association with cerebral asymmetry) has been presented for a gene for psychosis within the Xq21.3/Yp region of homology that is specific to Homo sapiens. We tested this hypothesis using the pentanucleotide marker DXYS 156 that is located within this region. In 84 families affected by schizophrenia or schizo‐affective disorder no tendency toward increased allele sharing amongst siblings was observed (χ2 = 0.002). We conclude either that this region does not include a gene predisposing to psychosis or that if it does, the relevant variation is epigenetic rather than sequence‐based. With respect to the latter possibility we draw attention to the recent evolutionary history of the Xq21.3/Yp region. Genes within the region are in transition to protection from X inactivation and therefore may be epigenetically labile. © 2002 Wiley‐Liss, Inc. 相似文献
89.
I C Francis G A Nicholson M B Kappagoda 《Australian and New Zealand journal of ophthalmology》1985,13(4):395-399
Fifteen patients with ocular myasthenia gravis were examined in detail for 21 different signs, and tested for acetylcholine receptor antibodies. The major signs of ocular myasthenia gravis included ptosis, disorders of ocular rotations, weakness of eyelid closure, "pseudosupranuclear" signs and the lid twitch sign. Acetylcholine receptor antibodies were found in eight of the 15 patients. One hundred and four normal, non-myasthenic patients were also examined for the lid twitch response, and the relationship between the lid twitch of ocular myasthenia gravis and that found in normal subjects is discussed. 相似文献
90.
Two types of phantoms were developed with which to evaluate the overall performance of digital subtraction angiography (DSA) systems. A dynamic phantom, called a "fish bone" phantom, consists of polyethylene tubes that simulate blood vessels with various lesions, such as stenoses, ulcers, and aneurysms. With this phantom, washout curves were obtained representing the relationship between iodine content and time. It will be useful for qualitative assessment of DSA images, evaluation of different image-processing schemes, and studies of blood flow analysis. A static phantom, called a "C-D" phantom, can be used for measurement of quantitative contrast-detail (C-D) diagrams and for daily monitoring of DSA systems. This was constructed of tubes of seven different diameters (2.15-0.28 mm) and 14 different concentrations of contrast medium (100%-1.1% Renografin-76 [meglumine and sodium diatrizoate]). The C-D diagrams were determined from an observer performance study using C-D phantom images obtained at four different DSA settings. 相似文献