全文获取类型
收费全文 | 14097篇 |
免费 | 1477篇 |
国内免费 | 358篇 |
专业分类
耳鼻咽喉 | 170篇 |
儿科学 | 390篇 |
妇产科学 | 253篇 |
基础医学 | 892篇 |
口腔科学 | 208篇 |
临床医学 | 1721篇 |
内科学 | 2938篇 |
皮肤病学 | 175篇 |
神经病学 | 699篇 |
特种医学 | 498篇 |
外国民族医学 | 3篇 |
外科学 | 2022篇 |
综合类 | 1714篇 |
现状与发展 | 2篇 |
预防医学 | 1271篇 |
眼科学 | 174篇 |
药学 | 1366篇 |
65篇 | |
中国医学 | 726篇 |
肿瘤学 | 645篇 |
出版年
2024年 | 52篇 |
2023年 | 589篇 |
2022年 | 799篇 |
2021年 | 1393篇 |
2020年 | 1288篇 |
2019年 | 1083篇 |
2018年 | 1011篇 |
2017年 | 832篇 |
2016年 | 676篇 |
2015年 | 602篇 |
2014年 | 1195篇 |
2013年 | 1140篇 |
2012年 | 728篇 |
2011年 | 699篇 |
2010年 | 508篇 |
2009年 | 518篇 |
2008年 | 465篇 |
2007年 | 417篇 |
2006年 | 354篇 |
2005年 | 270篇 |
2004年 | 229篇 |
2003年 | 159篇 |
2002年 | 144篇 |
2001年 | 97篇 |
2000年 | 72篇 |
1999年 | 58篇 |
1998年 | 71篇 |
1997年 | 69篇 |
1996年 | 56篇 |
1995年 | 43篇 |
1994年 | 38篇 |
1993年 | 36篇 |
1992年 | 35篇 |
1991年 | 25篇 |
1990年 | 21篇 |
1989年 | 21篇 |
1988年 | 19篇 |
1987年 | 14篇 |
1986年 | 11篇 |
1985年 | 24篇 |
1984年 | 19篇 |
1983年 | 13篇 |
1982年 | 10篇 |
1981年 | 10篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 5篇 |
1972年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 70 毫秒
101.
The atopy patch test -- reproducibility and comparison of different evaluation methods 总被引:2,自引:0,他引:2
Heinemann C Schliemann-Willers S Kelterer D Metzner U Kluge K Wigger-Alberti W Elsner P 《Allergy》2002,57(7):641-645
BACKGROUND: There is still a lack of standardization of the atopy patch test (APT) in test procedures and evaluation methods. Our aim was to examine the reproducibility of APT results and to compare visual evaluation to chromametry and laser Doppler imaging. METHODS: Fifty-two volunteers with atopic eczema/dermatitis syndrome (AEDS) were included. The APT was performed on tape-stripped and unstripped test fields on their backs using cat dander, house dust mite and grass pollen allergens from two different suppliers. Responders were re-tested 4-12 weeks later with the same allergens on their forearms. RESULTS: Using Allergopharma allergens, 14 (26.9%) volunteers showed one or more positive reactions. The reproducibility rate was 56.3%. The Erlangen atopy score in APT-positive and negative volunteers was 19 +/- 6 vs 15 +/- 6. The test agreement in volunteers tested with both allergens, from Allergopharma and Stallergènes, was poor. Correlation of the results between the three evaluation methods was significant (P < or = 0.001). CONCLUSIONS: The low reproducibility rate of APT results and the poor inter-test-agreement using allergens from different suppliers show that much work remains to make the APT a reliable tool in identifying relevant aeroallergens that lead to flare ups of AEDS. Compared to chromametry and laser Doppler imaging, visual scoring was superior in differentiation between irritative and allergic reactions. 相似文献
102.
Evaluation of the mixed lymphocyte culture (MLC) assay as a method for selecting unrelated donors for marrow transplantation 总被引:2,自引:0,他引:2
E. M. Mickelson G. Longton C. Anasetti E. Petersdorf P. Martin L. A. Guthrie J. A. Hansen 《Tissue antigens》1996,47(1):27-36
Abstract: The utility of the MLC assay as a test of HLA-D region matching and predictor of graft-versus-host disease (GvHD) was evaluated in 435 patients receiving marrow grafts from unrelated donors. Donors and recipients were phenotyped for HLA-A, B and DR antigens by serology, tested in MLC, and retrospectively genotyped for DRB1, B3, B4, B5, DQB1 and DPB1 alleles by PCR/SSOP. Of the 244 HLA-A, B, DR-identical donor-recipient pairs with evaluable MLC and DRB1 typing results available, 208 were matched for HLA-A, B and DRB1, while 36 were matched for HLA-A and B and mismatched for a DRB1 allele. Donor anti-recipient relative responses (RR) in MLC, corresponding to the GvHD vector in marrow transplantation, ranged from 7.2 to 100%, with a median of 4.0%. A comparison of reactivity in MLC between pairs matched versus mismatched for DRB1 alleles showed a significant overlap in the distribution of RRs. Using optimally-defined RR cutoffs of 4 and 16%, no correlation between MLC results and risk of developing clinically significant grades III-IV GvHD (p=0.6 and 0.5, respectively) was found when the contribution of DRB1 mismatch was accounted for. Matching for DRB1 alleles, in contrast, was a better predictor of clinically significant GvHD, with DRB1-matched transplant recipients less likely to develop grades III-IV GvHD than DRB1-mismatched recipients (p=0.14). Among the 208 patients and donors matched for DRB1 alleles, the MLC, although reactive (RR > 4.0%) in 45% of cases, did not predict GvHD. Overall, these results underscore the limitations in using the MLC to predict DRB1 matching or risk of clinically significant GvHD among patients receiving unrelated marrow grafts. The availability of DRB1 allele matching by sequence-specific oligonucleotide probes (SSOP) or by direct sequencing provides a method for donor matching that is rapid, precise and superior to the MLC for predicting clinically relevant outcome. 相似文献
103.
The use of a pretherapeutic, predictive score to determine inclusion criteria for the non-surgical treatment of ectopic pregnancy. 总被引:6,自引:1,他引:6
H Fernandez C Lelaidier V Thouvenez R Frydman 《Human reproduction (Oxford, England)》1991,6(7):995-998
Non-surgical management of ectopic pregnancy has recently become an alternative to surgery. We have investigated a pretherapeutic score to define the indication for non-surgical and surgical treatment in 61 patients with ectopic pregnancy. The score was performed before the patients' inclusion in a nonsurgical management scheme. The score used six criteria which were evaluated on a scale from 1 to 3: gestational age, human chorionic gonadotrophin (HCG) level, progesterone level, abdominal pain, haemoperitoneum volume and haematosalpinx diameter (estimated by laparoscopy or transvaginal ultrasound). Three scores, 10, 11 and 12, were studied in order to define a threshold beyond which surgical treatment should be performed. For each one, sensitivity, specificity and positive and negative predictive values were analysed. The success rate of non-surgical treatment was 75% (46/61). For patients undergoing medical treatment with a score less than or equal to 12, the success rate was significantly higher compared with a success rate of 50% when the score was greater than 12. We conclude that a score less than or equal to 12 permits non-surgical management with a success rate of 82%. A score greater than 12 indicates that laparoscopic surgery may be more suitable. The choice between different non-surgical approaches, did not influence the success rate. When ultrasound reveals embryo heart activity, medical treatment is always possible if the score is less than or equal to 12. 相似文献
104.
目的:回顾性分析急性胰腺炎(AP)患者空腹高血糖发生率及其危险因素。方法:收集2018-01—2018-12武汉大学人民医院胰腺外科133例AP且无糖尿病(DM)病史的住院患者病历资料,按照不同性别、年龄、AP临床分型、病因、CT指数评分(CISI)等分组,χ2检验分析各组临床因素与空腹高血糖(FPG≥6.1mmol/L)发生率的关系,多因素二元logistic回归分析空腹高血糖独立危险因素。结果:AP临床分型(χ2=5.494,P=0.019)和CTSI(χ2=6.236,P=0.013)与AP患者空腹高血糖相关(P<0.05)。CTSI≥6分(P=0.015,OR=2.920,95%Cl=1.234—6.905)为AP患者空腹高血糖的独立危险因素(P<0.05)。结论:临床分型中重症+重症及CTSI≥6分的AP患者易发生空腹高血糖,尤其CTSI≥6分是AP后空腹高血糖的独立危险因素,临床应高度关注。 相似文献
105.
Lack of PTEN expression in endometrial intraepithelial neoplasia is correlated with cancer progression 总被引:6,自引:0,他引:6
Baak JP Van Diermen B Steinbakk A Janssen E Skaland I Mutter GL Fiane B Løvslett K 《Human pathology》2005,36(5):555-561
We tested the hypothesis that PTEN inactivation may stratify cancer progression risk among putative endometrial hyperplasias, classified prognostically by means of the morphometric D score (DS). The DS, calculated from 3 morphometric variables measured in routine hematoxylin-eosin-stained endometrial biopsy slides, is the most sensitive and specific method of endometrial cancer risk prediction currently available. Clinical outcomes of 103 women with endometrial hyperplasia on biopsy were tallied according to the DS. Seven (7/103; 7%) patients with carcinoma during follow-up were all distributed within the high-risk prognostic group (ie, DS <1 = endometrial intraepithelial neoplasia [EIN]) (7/21; 33% progression). None of the 82 cases with a DS higher than 1 progressed. All cases that progressed were PTEN null, indicating that this genotype is capable of further stratifying cancer progression risk in hyperplasias irrespective of histological categorization. However, only 16% of the PTEN-null cases progressed. When PTEN expression pattern was combined with EIN, the prognostic power was greatly increased (specificity from 63% for PTEN and 85% for EIN to 93% when combined; positive predictive value from 16% and 33% to 50%). We conclude that loss of PTEN expression is the first biomarker in EIN that increases the accuracy of the prognostic DS to predict cancer progression risk. Unless endometrial hyperplasias are stratified by histological morphometric D-Score, PTEN has a low positive predictive value. 相似文献
106.
动态脑电图对缺血缺氧性昏迷病人的预后评估 总被引:4,自引:0,他引:4
目的:观察动态脑电图和临床检测指标对缺血缺氧性昏迷病人预后的评估价值。方法:在45例缺血缺氧性昏迷病人急性期进行动态脑电图检测和Glasgow评分、瞳孔对光反应、脑干反应检查,随访3个月时病人的预后,将动态脑电图检测和各项临床检查结果与病人的预后结果进行相关分析。结果:动态脑电图对昏迷病人预后的评估在敏感性(83.3%)、特异性(100%)和对预后评估的准确率(91.7%)方面均比临床检测结果高,临床指标Glasgow评分、瞳孔对光反射、脑干反射的敏感性、特异性及准确率分别为73.1%、84.2%及77.9%;76.9%、73.7%及75.6%;76.0%、68.4%及68.9%。结论:动态脑电图检测对急性缺血缺氧性昏迷病人预后的评估有确定的价值。 相似文献
107.
Araabi BN Kehtarnavaz N McKinney T Hillman G Würsig B 《Annals of biomedical engineering》2000,28(10):1269-1279
This paper presents a syntactic/semantic string representation scheme as well as a string matching method as part of a computer-assisted system to identify dolphins from photographs of their dorsal fins. A low-level string representation is constructed from the curvature function of a dolphin's fin trailing edge, consisting of positive and negative curvature primitives. A high-level string representation is then built over the low-level string via merging appropriate groupings of primitives in order to have a less sensitive representation to curvature fluctuations or noise. A family of syntactic/semantic distance measures between two strings is introduced. A composite distance measure is then defined and used as a dissimilarity measure for database search, highlighting both the syntax (structure or sequence) and semantic (attribute or feature) differences. The syntax consists of an ordered sequence of significant protrusions and intrusions on the edge, while the semantics consist of seven attributes extracted from the edge and its curvature function. The matching results are reported for a database of 624 images corresponding to 164 individual dolphins. The identification results indicate that the developed string matching method performs better than the previous matching methods including dorsal ratio, curvature, and curve matching. The developed computer-assisted system can help marine mammalogists in their identification of dolphins, since it allows them to examine only a handful of candidate images instead of the currently used manual searching of the entire database. © 2000 Biomedical Engineering Society.
PAC00: 8780Tq, 4230Sy, 0705Pj 相似文献
108.
C. Sorlié O. Bertrand B. Yvert J. -C. Froment J. Pernier 《Medical & biological engineering & computing》1997,35(3):239-245
A method has been developed to match a standard digitised brain atlas onto MR images for identification of cerebral structures
in anatomical images. This method uses, first, a three-dimensional crude registration based on the proportional system of
Talairach. Then, a two-dimensional refined registration is performed using a deformation function based on a set of homologous
landmarks on both images (MR and atlas). Displacements vectors are computed between each corresponding landmark. These vectors
are interpolated by thin-plate splines, generating an unwarping function defined on the whole image. This function can then
be applied on any structure of the atlas. An evaluation of the matching procedure has been performed. First, the influence
of the choice of the landmarks has been evaluated for the fine registration method. The latter has been then compared to the
crude registration method considered as a classical reference method. These results show the advantages of the fine registration
approach. 相似文献
109.
Evolution of sleep and sleep EEG after hemispheric stroke 总被引:3,自引:0,他引:3
Vock J Achermann P Bischof M Milanova M Müller C Nirkko A Roth C Bassetti CL 《Journal of sleep research》2002,11(4):331-338
The evolution of subjective sleep and sleep electroencephalogram (EEG) after hemispheric stroke have been rarely studied and the relationship of sleep variables to stroke outcome is essentially unknown. We studied 27 patients with first hemispheric ischaemic stroke and no sleep apnoea in the acute (1-8 days), subacute (9-35 days), and chronic phase (5-24 months) after stroke. Clinical assessment included estimated sleep time per 24 h (EST) and Epworth sleepiness score (ESS) before stroke, as well as EST, ESS and clinical outcome after stroke. Sleep EEG data from stroke patients were compared with data from 11 hospitalized controls and published norms. Changes in EST (>2 h, 38% of patients) and ESS (>3 points, 26%) were frequent but correlated poorly with sleep EEG changes. In the chronic phase no significant differences in sleep EEG between controls and patients were found. High sleep efficiency and low wakefulness after sleep onset in the acute phase were associated with a good long-term outcome. These two sleep EEG variables improved significantly from the acute to the subacute and chronic phase. In conclusion, hemispheric strokes can cause insomnia, hypersomnia or changes in sleep needs but only rarely persisting sleep EEG abnormalities. High sleep EEG continuity in the acute phase of stroke heralds a good clinical outcome. 相似文献
110.
C V Steer C L Mills S L Tan S Campbell R G Edwards 《Human reproduction (Oxford, England)》1992,7(1):117-119
In order to achieve a clinical pregnancy rate higher than that achieved following initial adoption of in-vitro fertilization embryo transfers, more than one embryo is transferred. This has led to a substantial increase in unwanted multiple pregnancy rates with IVF as compared with natural conception. What is therefore required is a simple, clinically useful embryo scoring system, to reflect embryo developmental potential, which will enable the selection of the optimal number of embryos to transfer in order to achieve the maximum pregnancy rate with a low incidence of high order multiple pregnancies. We believe that the Cumulative Embryo Score (CES) achieves these aims. On the day of embryo transfer the grade of each embryo transferred was multiplied by the number of blastomeres to produce a score for each embryo, and summation of the scores obtained for all the embryos transferred gave the CES. The grouped pregnancy rates obtained rose as the CES increased to maximum of 42. A continued increase in the CES above 42 did not result in any further rise in the pregnancy rate. However, an analysis of all our IVF pregnancies showed that the multiple pregnancy rate continued to rise above a CES of 42. By restricting the CES per embryo transfer to 42, 78% of triplet pregnancies and 100% of the quadruplet IVF pregnancies could have been predicted and potentially avoided. 相似文献