全文获取类型
收费全文 | 5920篇 |
免费 | 439篇 |
国内免费 | 17篇 |
专业分类
耳鼻咽喉 | 74篇 |
儿科学 | 123篇 |
妇产科学 | 102篇 |
基础医学 | 1040篇 |
口腔科学 | 68篇 |
临床医学 | 547篇 |
内科学 | 1242篇 |
皮肤病学 | 89篇 |
神经病学 | 571篇 |
特种医学 | 277篇 |
外国民族医学 | 1篇 |
外科学 | 676篇 |
综合类 | 78篇 |
一般理论 | 4篇 |
预防医学 | 478篇 |
眼科学 | 139篇 |
药学 | 413篇 |
中国医学 | 22篇 |
肿瘤学 | 432篇 |
出版年
2023年 | 22篇 |
2022年 | 37篇 |
2021年 | 77篇 |
2020年 | 48篇 |
2019年 | 83篇 |
2018年 | 100篇 |
2017年 | 85篇 |
2016年 | 89篇 |
2015年 | 93篇 |
2014年 | 161篇 |
2013年 | 243篇 |
2012年 | 326篇 |
2011年 | 302篇 |
2010年 | 217篇 |
2009年 | 174篇 |
2008年 | 257篇 |
2007年 | 285篇 |
2006年 | 273篇 |
2005年 | 266篇 |
2004年 | 283篇 |
2003年 | 284篇 |
2002年 | 285篇 |
2001年 | 231篇 |
2000年 | 276篇 |
1999年 | 223篇 |
1998年 | 89篇 |
1997年 | 85篇 |
1996年 | 106篇 |
1995年 | 75篇 |
1994年 | 61篇 |
1993年 | 85篇 |
1992年 | 110篇 |
1991年 | 118篇 |
1990年 | 97篇 |
1989年 | 83篇 |
1988年 | 76篇 |
1987年 | 63篇 |
1986年 | 63篇 |
1985年 | 50篇 |
1984年 | 40篇 |
1983年 | 38篇 |
1982年 | 50篇 |
1981年 | 38篇 |
1980年 | 24篇 |
1979年 | 62篇 |
1978年 | 26篇 |
1977年 | 22篇 |
1976年 | 23篇 |
1975年 | 23篇 |
1973年 | 20篇 |
排序方式: 共有6376条查询结果,搜索用时 625 毫秒
71.
Contrasting in vitro effects of retinol and mononuclear cell factor on young and old human cartilage
O Huber-Bruning B Wilbrink J E Vernooij J W Bijlsma W Den Otter J Huber 《The Journal of pathology》1986,150(1):21-27
Studies with young animal cartilage have shown that retinol and mononuclear cell-factor (MCF) cause in vitro breakdown of the cartilage, mediated by the living chondrocyte (indirect degradation). We studied the effects of retinol and MCF on healthy human articular cartilage of different ages, measuring the effects on proteoglycan (PG) content of the cartilage, and on PG synthesis during 8 days of culture. This study shows: Retinol and MCF induce indirect degradation of young, but not of old human cartilage of the humeral head; Both retinol and MCF suppress PG synthesis of young and stimulate PG synthesis of old cartilage; The effects of retinol and MCF on cartilage PG content and on PG synthesis are related to the metabolic state of the chondrocyte; Therefore mononuclear cell-factor may have a destructive or beneficial effect on cartilage depending on whether proteoglycan synthesizing activity is high or low, respectively. 相似文献
72.
Two autoimmune disease models were studied in rhesus monkeys: type II collagen-induced arthritis (CIA) and experimental allergic encephalomyelitis (EAE). Unrelated outbred animals were used in these studies. In both models disease resistant and susceptible individuals could be identified. Susceptibility correlated with in vitro cellular responsiveness to antigen in the CIA model. In both models resistant as well as susceptible individuals developed a humoral response to the inducing antigen. However, there is an indication that IgM antibodies play a crucial role in the induction of CIA. No clear association between major histocompatibility complex (MHC) type and disease incidence was found although a higher frequency of a certain DR type was observed in EAE susceptible monkeys. It is likely that both the antigen binding capacity of the MHC class II molecules and the T-cell repertoire play an important role in determining whether disease will develop or not. 相似文献
73.
Non-sentinel lymph node involvement in patients with breast cancer and sentinel node micrometastasis; too early to abandon axillary clearance 总被引:7,自引:0,他引:7
den Bakker MA van Weeszenberg A de Kanter AY Beverdam FH Pritchard C van der Kwast TH Menke-Pluymers M 《Journal of clinical pathology》2002,55(12):932-935
AIMS: It has been suggested that patients with T1-2 breast tumours and sentinel node (SLN) micrometastases, defined as foci of tumour cells smaller than 2 mm, may be spared completion axillary lymph node dissection because of the low incidence of further metastatic disease. To gain insight into the extent of non-sentinel lymph node (n-SLN) involvement, SLNs and complementary axillary clearance specimens in patients with SLN micrometastases were examined. METHODS: A set of 32 patients with SLN micrometastases was selected on the basis of pathology reports and review of SLNs. Five hundred and thirteen n-SLNs from the axillary clearance specimens were serially sectioned and analysed by means of immunohistochemistry for metastatic disease. Lymph node metastases were grouped as macrometastases (> 2 mm), and micrometastases (< 2 mm), and further subdivided as isolated tumour cells (ITCs) or clusters. RESULTS: In 11 of 32 patients, one or more n-SLN was involved. Grade 3 tumours and tumours > 2 cm (T2-3 v T1) were significantly associated with n-SLN micrometastases as clusters (grade: odds ratio (OR), 8.3; 95% confidence interval (CI), 1.4 to 50.0; size: T2-3 tumours v T1: OR, 15; 95% CI, 2.18 to 103.0). However, no subgroup of tumours with regard to size and grade was identified that did not have n-SLN metastases. CONCLUSIONS: In patients with breast cancer and SLN micrometastases, n-SLN involvement is relatively common. The incidence of metastatic clusters in n-SLN is greatly increased in patients with T2-3 tumours and grade 3 tumours. Therefore, axillary lymph node dissection is especially warranted in these patients. However, because n-SLN metastases also occur in T1 and low grade tumours, even these should be subjected to routine axillary dissection to achieve local control. 相似文献
74.
Fluctuating asymmetries are small random deviations from perfect symmetry in bilateral traits caused by the inability of individuals to cope with stress during development. The degree of asymmetry of secondary sexual characters is supposed to convey information about a male's phenotypic and/or genetic quality, and females are thus expected to use bilateral symmetry as a cue in mate choice. We offered female three-spined sticklebacks (Gasterosteus aculeatus L.) that had been inbred for one generation and outbred control females the choice between computer-animated male models differing exclusively in the symmetry of their pelvic spines. Inbred females exhibited a significantly stronger preference for the symmetric model than outbred females, suggesting that females of relatively poor quality are more prepared to pay the costs of choosiness and obtain higher marginal benefits from their discrimination than females of better quality. 相似文献
75.
Burwinkel B; Maichele AJ; Aagenaes O; Bakker HD; Lerner A; Shin YS; Strachan JA; Kilimann MW 《Human molecular genetics》1997,6(7):1109-1115
Glycogen storage disease due to phosphorylase kinase deficiency occurs in
several variants that differ in mode of inheritance and tissue-
specificity. This heterogeneity is suspected to be largely due to mutations
affecting different subunits and isoforms of phosphorylase kinase. The gene
of the ubiquitously expressed beta subunit, PHKB, was a candidate for
involvement in autosomally transmitted phosphorylase kinase deficiency of
liver and muscle. To identify such mutations, the complete PHKB coding
sequence was amplified by RT-PCR of RNA isolated from blood samples of
patients and analyzed by direct sequencing of PCR products. The
characterization of mutations was complemented by PCR of genomic DNA. In
one female and four male patients, we identified five independent nonsense
mutations (Y418ter; R428ter; Y974H+E975ter; Q656ter in two cases), one
single-base insertion in codon N421, one splice-site mutation affecting
exon 31, and a large deletion involving the loss of exon 8. Although these
severe translation-disrupting mutations occur in constitutively expressed
sequences of the only known beta subunit gene of phosphorylase kinase,
PHKB, they are associated with a surprisingly mild clinical phenotype,
affecting virtually only the liver, and relatively high residual enzyme
activity of approximately 10%.
相似文献
76.
Kikuyoshi Yoshida Timo K. Van Den Berg Christine D. Dijkstra 《European journal of immunology》1994,24(2):464-468
In the present study, we have investigated the capacity of follicular dendritic cells (FDC) to trap immune complexes (IC) in the splenic white pulp of severe combined immunodeficient (SCID) mice and the influence of lymphocyte transfer on FDC function. FDC are absent in the splenic white pulp of naive SCID mice as revealed by in vitro IC trapping assay. One week after transfer of syngeneic lymphocytes, functional FDC with complement receptors appeared in the primary follicles coincident with B cell segregation, and IC were trapped on those FDC in a complement-dependent manner. Next, we immunized the reconstituted SCID mouse to see whether another type of FDC could be induced in the secondary follicle. Antigenic stimulation induced FDC with an additional capacity to capture IC via FcR γ II. As seen in immunocompetent mice, this type of FDC was located only in the light zone of the secondary follicle. The newly generated FDC did not carry H-2 antigen of transferred lymphocytes from F1 mice. In SCID mice, in which normally no functional FDC are detectable, the microenvironments of the splenic white pulp have a capacity to develop and differentiate normally after transfer of lymphocytes. Apparently, the generation of functional IC-trapping FDC causes the induction of complement receptor(s) and Fc receptor on meshwork cells, which requires the presence of the lymphocytes. 相似文献
77.
White RG Orroth KK Korenromp EL Bakker R Wambura M Sewankambo NK Gray RH Kamali A Whitworth JA Grosskurth H Habbema JD Hayes RJ 《Journal of acquired immune deficiency syndromes (1999)》2004,37(4):1500-1513
OBJECTIVE: To determine whether population differences can explain the contrasting impacts on HIV observed in the Mwanza trial of sexually transmitted disease (STD) syndromic treatment (ST), the Rakai trial of STD mass treatment (MT), and the Masaka trial of information, education, and communication (IEC) with and without ST as well as to predict the effectiveness of each intervention strategy in each population. METHODS: Stochastic modeling of the transmission of HIV and 6 STDs was used with parameters fitted to demographic, sexual behavior, and epidemiological data from the trials and general review of STD/HIV biology. RESULTS: The baseline trial populations could be simulated by assuming higher risk behavior in Uganda compared with Mwanza in the 1980s, followed by reductions in risk behavior in Uganda preceding the trials. In line with trial observations, the projected HIV impacts were larger for the ST intervention in Mwanza than for the MT intervention in Rakai or the IEC and IEC + ST interventions in Masaka. All 4 simulated intervention strategies were more effective in reducing incidence of HIV infection in Mwanza than in either Rakai or Masaka. CONCLUSIONS: Population differences in sexual behavior, curable STD rates, and HIV epidemic stage can explain most of the contrast in HIV impact observed between the 3 trials. This study supports the hypothesis that STD management is an effective HIV prevention strategy in populations with a high prevalence of curable STDs, particularly in an early HIV epidemic. 相似文献
78.
Magdy S. Aly Paola Dal Cin Herman Van Den Berghe Wim Van De Voorde Hein Van Poppel Filip Ameye Luc Baert 《Genes, chromosomes & cancer》1994,9(4):227-233
We combined conventional cytogenetic analysis and fluorescence in situ hybridization of short-term cultures of 28 samples from benign prostatic hyperplasia. Lou of the Y chromosome was the most common chromosome change, followed by trisomy 7. Trisomy 7, however, may be unrelated to the origin of benign prostate hyperplasia, in which the only and not very specific change seems to be the loss of the Y chromosome. Genes Chrom Cancer 9:227-233 (1594). © 1994 Wiley-Liss, Inc. 相似文献
79.
Paola Dal Cin Chris De Wolf-Peeters Magdy S. Aly Georges Deneffe Walter Van Mieghem Herman Van Den Berghe 《Genes, chromosomes & cancer》1993,6(4):243-244
Cytogenetic analysis of a thymoma showed the presence of a ring chromosome 6 as the sole chromosome abnormality. © 1993 Wiley-Liss, Inc. 相似文献
80.
Griffin JF Spittle E Rodgers CR Liggett S Cooper M Bakker D Bannantine JP 《Clinical and diagnostic laboratory immunology》2005,12(12):1401-1409
This study was designed to develop a customized enzyme-linked immunosorbent assay (ELISA) for the serodiagnosis of Johne's disease (JD) in farmed deer. Two antigens were selected on the basis of their superior diagnostic readouts: denatured purified protein derivative (PPDj) and undenatured protoplasmic antigen (PpAg). ELISA development was based on the antigen reactivity of the immunoglobulin G1 (IgG1) isotype, which is a highly specific marker for mycobacterial disease seroreactivity in deer. Sensitivity estimates and test parameters were established using 102 Mycobacterium paratuberculosis-infected animals from more than 10 deer herds, and specificity estimates were determined using 508 uninfected animals from 5 known disease-free herds. A receiver-operated characteristic analysis determined that at a cut point of 50 ELISA units, there was a specificity of 99.5% and sensitivities of 84.0% with PPDj antigen, 88.0% with PpAg, and 91.0% when the antigens were used serially in a composite test. Estimated sensitivity was further improved using recombinant protein antigens unique for M. paratuberculosis, which identified infected animals that were unreactive to PPDj or PpAg. While 80% of animals that were seropositive in the IgG1 ELISA had detectable histopathology, the assay could also detect animals with subclinical disease. The test was significantly less sensitive (75%) for animals that were culture positive for M. paratuberculosis but with no detectable pathology than for those with pathological evidence of JD (>90%). When the IgG1 ELISA was used annually over a 4-year period in a deer herd with high levels of clinical JD, it eliminated clinical disease, increased production levels, and reduced JD-related mortality. 相似文献