全文获取类型
收费全文 | 5360篇 |
免费 | 408篇 |
国内免费 | 46篇 |
专业分类
耳鼻咽喉 | 57篇 |
儿科学 | 133篇 |
妇产科学 | 133篇 |
基础医学 | 626篇 |
口腔科学 | 74篇 |
临床医学 | 453篇 |
内科学 | 1049篇 |
皮肤病学 | 108篇 |
神经病学 | 409篇 |
特种医学 | 207篇 |
外科学 | 976篇 |
综合类 | 370篇 |
一般理论 | 3篇 |
预防医学 | 300篇 |
眼科学 | 106篇 |
药学 | 376篇 |
中国医学 | 64篇 |
肿瘤学 | 370篇 |
出版年
2023年 | 44篇 |
2022年 | 46篇 |
2021年 | 88篇 |
2020年 | 85篇 |
2019年 | 107篇 |
2018年 | 135篇 |
2017年 | 98篇 |
2016年 | 102篇 |
2015年 | 140篇 |
2014年 | 188篇 |
2013年 | 203篇 |
2012年 | 309篇 |
2011年 | 273篇 |
2010年 | 189篇 |
2009年 | 184篇 |
2008年 | 260篇 |
2007年 | 280篇 |
2006年 | 319篇 |
2005年 | 280篇 |
2004年 | 284篇 |
2003年 | 234篇 |
2002年 | 236篇 |
2001年 | 197篇 |
2000年 | 154篇 |
1999年 | 179篇 |
1998年 | 82篇 |
1997年 | 93篇 |
1996年 | 71篇 |
1995年 | 66篇 |
1994年 | 59篇 |
1993年 | 24篇 |
1992年 | 88篇 |
1991年 | 121篇 |
1990年 | 77篇 |
1989年 | 48篇 |
1988年 | 55篇 |
1987年 | 47篇 |
1986年 | 44篇 |
1985年 | 46篇 |
1984年 | 34篇 |
1983年 | 20篇 |
1982年 | 25篇 |
1981年 | 20篇 |
1980年 | 20篇 |
1979年 | 17篇 |
1978年 | 21篇 |
1977年 | 14篇 |
1975年 | 17篇 |
1973年 | 18篇 |
1972年 | 13篇 |
排序方式: 共有5814条查询结果,搜索用时 15 毫秒
71.
Identification of Potential Diagnostic and Vaccine Candidates of Helicobacter pylori by Two-Dimensional Gel Electrophoresis, Sequence Analysis, and Serum Profiling 总被引:3,自引:0,他引:3 下载免费PDF全文
C. Patrick McAtee Moon Young Lim Kevin Fung Mark Velligan Kirk Fry Theresa Chow Douglas E. Berg 《Clinical and Vaccine Immunology : CVI》1998,5(4):537-542
There is great interest in characterizing the proteins of the gastric pathogen Helicobacter pylori, especially those to which humans respond immunologically, because of the potential importance of such proteins in diagnosis and vaccine development. Two-dimensional gel electrophoresis was used to separate and identify potential antigens of H. pylori ATCC 43504. Over 30 proteins were reactive in Western blots with pooled sera from 14 infected patients. These proteins were analyzed by N-terminal sequence analysis. Fourteen proteins were determined to be distinct from any proteins previously described from H. pylori; the others were previously isolated and characterized proteins. Analysis of eight distinct H. pylori strains showed that most of these antigens were produced by all of the strains. We propose that collection of new antigens such as those recognized here will be useful in serologic tests for detecting and monitoring H. pylori infection and may also serve as potential targets for antimicrobial agent or vaccine development. 相似文献
72.
Synergistic effect of IL-4 and TNF-alpha in the induction of monocytic differentiation of a mouse myeloid leukaemic cell line (WEHI-3B JCS). 总被引:1,自引:0,他引:1 下载免费PDF全文
We have previously shown that non-cytotoxic concentrations (600-1200 U/ml) of recombinant mouse tumour necrosis factor-alpha (TNF-alpha) can induce differentiation of a subclone (JCS) of the WEHI-3B myelomonocytic leukaemia cell line into mature cells with the characteristics of macrophages. In the present study, the effects of recombinant mouse interleukin-4 (IL-4), either alone or in combination with mouse TNF-alpha, on the growth and differentiation of JCS cells were examined. IL-4 alone (20-5000 U/ml) inhibited the growth of JCS cells in a dose-dependent manner but did not induce cell differentiation. However, combinations of IL-4 and TNF-alpha acted in synergy to inhibit cell proliferation and induce monocytic differentiation of JCS cells, as shown by increased expression of the macrophage differentiation antigens (F4/80, Mac-1), stimulation of phagocytic activity, induction of non-specific esterase and NBT-reducing activities, increased plastic adherence and morphological criteria. Similar synergistic interactions were also shown by human TNF-alpha and mouse IL-4, indicating that TNF-alpha might exert its effects through the low-affinity (p55) TNF receptors. Moreover, the clonogenicity of JCS cells in vitro and their tumorigenicity in vivo were significantly reduced by combined TNF-alpha and IL-4 treatment. Our results indicate that TNF-alpha can act as a differential signal for JCS cells and that its effects are modulated by IL-4. Therefore, the combination of TNF-alpha and IL-4 may be useful in the treatment of some forms of myelomonocytic leukaemia. 相似文献
73.
AIMS: To define epidemiology, clinical disease, and outcome of gemella bacteraemia by 16S rRNA gene sequencing. To examine the usefulness of the Vitek, API, and ATB systems in identifying two gemella species. METHODS: All alpha haemolytic streptococci other than Streptococcus pneumoniae isolated from blood cultures during a six year period were identified by conventional biochemical methods, the Vitek system, and the API system. 16S rRNA gene sequencing was performed on all isolates identified by both kits as gemella with >or= 95% confidence or by either kit as any bacterial species with < 95% confidence. The ATB expression system was used to identify the two isolates that were defined as gemella species by 16S rRNA gene sequencing. RESULTS: Of the 302 alpha haemolytic streptococci other than S pneumoniae isolated, one was identified as Gemella morbillorum, and another as Gemella haemolysans by 16S rRNA gene sequencing. The patient with monomicrobial G morbillorum bacteraemia was a 66 year old man with community acquired infective endocarditis with septic thromboemboli. The patient with G haemolysans bacteraemia was a 41 year old woman with hospital acquired polymicrobial bacteraemia during the neutropenic period of an autologous bone marrow transplant for non-Hodgkin's lymphoma, the first case of its kind in the English literature. The API and ATB expression systems only identified the second strain as G haemolysans at 94% and 99% confidence, respectively, whereas the Vitek system identified none of the two strains correctly at > 70% confidence. CONCLUSIONS: Gemella bacteraemia is uncommon. 16S rRNA gene sequencing is the method of choice for identification of gemella and gemella-like isolates. 相似文献
74.
Fung AY 《Physics in medicine and biology》2002,47(16):N203-N208
Patients with advanced gynaecological cancer are often treated with a temporary interstitial implant using the Syed template and Ir- 192 ribbons at the Memorial Sloan-Kettering Cancer Center. Urgency in planning is great. We created a computerized inverse planning system for the Syed temporary gynaecological implant, which optimized the ribbon strengths a few seconds after catheter digitization. Inverse planning was achieved with simulated annealing. We discovered that hand-drawn target volumes had drawbacks; hence instead of producing a grid of points based on target volume, the optimization points were generated directly from the catheter positions without requiring an explicit target volume. Since all seeds in the same ribbon had the same strength, the minimum doses were located at both ends of the implant. Optimization points generated at both ends ensured coverage of the whole implant. Inverse planning took only a few seconds, and generated plans that provide a good starting point for manual improvement. 相似文献
75.
Huang W Sher YP Delgado-West D Wu JT Peck K Fung YC 《Annals of biomedical engineering》2001,29(7):535-551
The remodeling of the pulmonary arterial tissue in response to a step change of the oxygen concentration in the gas in which a rat lives was recorded as function of time and function of O2 concentration. Three steps of changing from 20.9% to 17.2%, 13.6%, and 10% O2 were imposed. Earlier work in our laboratory has shown that pulmonary arterial tissue remodeling is significant in the first 24 h after a step change of oxygen tension. Hence we made measurements in this period. Furthermore, data were obtained for tissue remodeling of circumferential and axial lengths of the pulmonary arteries. We recorded the activities of gene expressions in the lung tissues by microarray, determined the dose response curves of gene expression in the homogenized whole lungs with respect to four levels of O2 concentration, and obtained the time courses of gene expression in the lung parenchyma in 30 days after a step decrease of O2 concentration from 20.9% to 10%. We would like to suggest that the correlation of gene expression with physiological function parameters, i.e., time, O2 tension, blood pressure, opening angle, wall thicknesses, etc., is the way to narrow down the search for specific genes for specific physiological functions. © 2001 Biomedical Engineering Society.
PAC01: 8719Uv 相似文献
76.
Wang M Tzeng TY Fung CY Ou WC Tsai RT Lin CK Tsay GJ Chang D 《Journal of virological methods》1999,78(1-2):171-176
The immunoreactivity of human anti-JC virus (JCV) serum against the major capsid protein VP1 of JCV was analyzed by Western blot, dot blot, and hemagglutination inhibition (HAI) assays. JCV-positive human serum reacted with native but not denatured JCV major capsid protein VP1, as demonstrated by dot blot and Western blot. Rabbit antiserum raised against native JCV capsid had immunoreactivities similar to those of human anti-JCV serum. These results indicate that the antigenecity of native and denatured JCV VP1 is different. In addition, both JCV-positive human serum and rabbit antiserum raised against native JCV capsid protein inhibited the hemagglutination activity of JCV capsid particles. In contrast, rabbit antiserum raised against denatured JCV VP1 did not inhibit hemagglutination. These findings reveal that denaturation may alter the antigenic epitopes of JCV VP1. Therefore, keeping the JCV capsid protein native appears to be essential for serological or other immunological analyses of the virus. 相似文献
77.
High throughput parallel analysis of hundreds of patient samples for more than 100 mutations in multiple disease genes 总被引:5,自引:0,他引:5
Shuber AP; Michalowsky LA; Nass GS; Skoletsky J; Hire LM; Kotsopoulos SK; Phipps MF; Barberio DM; Klinger KW 《Human molecular genetics》1997,6(3):337-347
As more mutations are identified in genes of known sequence, there is a
crucial need in the areas of medical genetics and genome analysis for
rapid, accurate and cost-effective methods of mutation detection. We have
developed a multiplex allele-specific diagnostic assay (MASDA) for analysis
of large numbers of samples (> 500) simultaneously for a large number of
known mutations (> 100) in a single assay. MASDA utilizes
oligonucleotide hybridization to interrogate DNA sequences. Multiplex DNA
samples are immobilized on a solid support and a single hybridization is
performed with a pool of allele-specific oligonucleotide (ASO) probes. Any
probes complementary to specific mutations present in a given sample are in
effect affinity purified from the pool by the target DNA. Sequence-specific
band patterns (fingerprints), generated by chemical or enzymatic sequencing
of the bound ASO(s), easily identify the specific mutation(s). Using this
design, in a single diagnostic assay, we tested samples for 66 cystic
fibrosis (CF) mutations, 14 beta-thalassemia mutations, two sickle cell
anemia (SCA) mutations, three Tay-Sachs mutations, eight Gaucher mutations,
four mutations in Canavan disease, four mutations in Fanconi anemia, and
five mutations in BRCA1. Each mutation was correctly identified. Finally,
in a blinded study of 106 of these mutations in > 500 patients, all
mutations were properly identified. There were no false positives or false
negatives. The MASDA assay is capable of detecting point mutations as well
as small insertion or deletion mutations. This technology is amenable to
automation and is suitable for immediate utilization for high-throughput
genetic diagnostics in clinical and research laboratories.
相似文献
78.
The t(X;1)(p11.2;q21.2) translocation in papillary renal cell carcinoma fuses a novel gene PRCC to the TFE3 transcription factor gene 总被引:4,自引:2,他引:4
79.
80.
Metes D Logar A Rudert WA Zeevi A Woodward J Demetris AJ Abu-Elmagd K Eghtesad B Shapiro R Fung JJ Trucco M Starzl TE Murase N 《Human immunology》2003,64(8):787-795
Passenger leukocytes have been demonstrated to play significant roles in initiating and also regulating immune reactions after organ transplantation. Reliable techniques to detect donor leukocytes in recipients after organ transplantation are essential to analyze the role, function, and behavior of these leukocytes. In this report we describe a simple, reliable method to detect donor cells with low frequencies using peripheral blood samples. Detection of small numbers of major histocompatibility complex (MHC) mismatched cells was first studied using four-color flow cytometry in artificially created cell mixtures. By selecting the CD45(+) population and simultaneous staining with several leukocyte lineage markers (CD3, CD4, CD8, CD56, and CD19), MHC-mismatched leukocytes were consistently detected in cell suspensions prepared from directly stained whole blood samples with a threshold sensitivity as low as 0.1%-0.2%. When the fresh peripheral blood mononuclear cells were separated by conventional Ficoll gradient purification, similar, but slightly lower levels of donor cells were detected. Blood samples obtained 1-5 months after liver, kidney, and intestine transplants revealed that the kind of organ allograft influenced levels and lineage pattern of the circulating donor cells. This procedure provided a simple and reliable method in determining early chimerism in transplant recipients. However, the detection of MHC-mismatched leukocytes of all lineages was much lower when frozen peripheral blood mononuclear cells were used. 相似文献