全文获取类型
收费全文 | 11643篇 |
免费 | 683篇 |
国内免费 | 57篇 |
专业分类
耳鼻咽喉 | 189篇 |
儿科学 | 191篇 |
妇产科学 | 200篇 |
基础医学 | 1728篇 |
口腔科学 | 1028篇 |
临床医学 | 989篇 |
内科学 | 2645篇 |
皮肤病学 | 258篇 |
神经病学 | 762篇 |
特种医学 | 281篇 |
外科学 | 1355篇 |
综合类 | 42篇 |
一般理论 | 5篇 |
预防医学 | 1197篇 |
眼科学 | 118篇 |
药学 | 884篇 |
2篇 | |
中国医学 | 146篇 |
肿瘤学 | 363篇 |
出版年
2023年 | 141篇 |
2022年 | 236篇 |
2021年 | 449篇 |
2020年 | 294篇 |
2019年 | 385篇 |
2018年 | 483篇 |
2017年 | 325篇 |
2016年 | 343篇 |
2015年 | 402篇 |
2014年 | 522篇 |
2013年 | 686篇 |
2012年 | 936篇 |
2011年 | 1084篇 |
2010年 | 519篇 |
2009年 | 427篇 |
2008年 | 650篇 |
2007年 | 669篇 |
2006年 | 579篇 |
2005年 | 490篇 |
2004年 | 400篇 |
2003年 | 336篇 |
2002年 | 336篇 |
2001年 | 216篇 |
2000年 | 213篇 |
1999年 | 175篇 |
1998年 | 62篇 |
1997年 | 62篇 |
1996年 | 39篇 |
1995年 | 45篇 |
1994年 | 52篇 |
1993年 | 32篇 |
1992年 | 91篇 |
1991年 | 59篇 |
1990年 | 67篇 |
1989年 | 63篇 |
1988年 | 41篇 |
1987年 | 34篇 |
1986年 | 35篇 |
1985年 | 39篇 |
1984年 | 24篇 |
1983年 | 22篇 |
1980年 | 21篇 |
1979年 | 21篇 |
1978年 | 27篇 |
1976年 | 21篇 |
1975年 | 21篇 |
1973年 | 22篇 |
1971年 | 21篇 |
1970年 | 17篇 |
1969年 | 18篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
Câmara EJ Braga JC Alves-Silva LS Câmara GF da Silva Lopes AA 《Cardiology in the young》2002,12(2):119-124
OBJECTIVES: To compare the short-term prognosis of patients with severe acute rheumatic carditis when treated with an intravenous pulse of methylprednisolone in comparison with conventional treatment using oral prednisone. METHODS: We designed a randomized clinical trial in the setting of a university general hospital in Brazil. We randomly allocated 18 patients with the diagnosis of severe acute rheumatic carditis and congestive heart failure to receive an intravenous pulse as opposed to oral prednisolone. Methylprednisolone was administered in a dose of 1 g intravenously for 3 consecutive days in the first and second weeks, for two days in the third, and one day in the fourth week. Prednisone was administered in a dose of 1.5 mg/kg/day over the period of 4 weeks. RESULTS: The mean age of the patients was 11.1 +/- 3.7 years, with a median of 12 years. Patients on oral treatment showed a more pronounced decrease in the heart rate, sedimentation rate, and in the titres of C-reactive protein than those receiving intravenous therapy. At the end of treatment, a mild decrease in the left ventricular end-systolic dimension was found in those having oral treatment, compared to an increase in the group having intravenous treatment (p = 0.036). The ejection fraction showed a median increase of 5% in those undergoing oral treatment, and a median decrease of 6% in the group with intravenous therapy (p = 0.009). There were 5 therapeutic failures in those receiving intravenous therapy (56%), including 1 death. Therapeutic failures were not observed in those treated orally (p = 0.03). CONCLUSION: Intravenous treatment of methylprednisolone, as a single anti-inflammatory agent, was inferior to conventional treatment with oral prednisone in the control of severe rheumatic carditis. 相似文献
132.
Segreto HR Ferreira AT Kimura ET Franco M Egami MI Silva MR Segreto RA 《American journal of hematology》2002,71(3):143-151
Experiments were undertaken to assess the role of amifostine in the activation of latent TGFbeta1 and in the smad proteins cascade (smad 2/3, smad4, smad7), focusing on megakaryocytes, in the bone marrow irradiated in vivo. Non-irradiated megakaryocytes were negative for active TGFbeta1. Immunopositivity to active TGFbeta1 was detected in megakaryocytes 10 days after irradiation in amifostine- treated and untreated marrows. Smad 2/3 and smad 4 were strongly positive in the nucleus of megakaryocytes 10 days after irradiation. At the same time, a predominant hypocellular bone marrow with foci of hematopoiesis was observed with few megakaryocytes. An increase in the number of reticulin fibers was also seen. In amifostine-treated marrows, smad 2/3 and smad4 were not detected in the nucleus but were positive in the cytoplasm of megakaryocytes 10 days after irradiation. Coincidentally, bone marrows were cellular with megakaryocytes. Smad7 immunoexpression was detected in the cytoplasm of megakaryocytes in the non-irradiated, amifostine-treated and in the irradiated, amifostine-treated marrows. Data indicate that amifostine does not prevent latent TGFbeta1 activation in irradiated megakaryocytes. While TGFbeta1 signal transduction occurs in megakaryocytes in untreated bone marrows, it is inhibited in megakaryocytes in amifostine-treated marrows due to the induction of smad 7 activation. This is the first report showing smad 7 activation by amifostine. Our results also suggest a role for TGFbeta1 as an inhibitor of megakaryocytes in vivo. 相似文献
133.
Sylvatic triatomines of the genus Rhodnius commonly fly into houses in Latin America, maintaining the risk of Chagas disease transmission in spite of control efforts. In the recent past, adult bugs collected inside houses in central Brazil were identified as R. prolixus, a primary disease vector whose natural geographical range excludes this region. Three nearly sibling species (R. neglectus, R. nasutus, and R. robustus), secondary vectors with limited epidemiological significance, occur naturally south of the Brazilian Amazon. The specific status of Rhodnius specimens found inside houses in central Brazil is therefore an epidemiologically important (and still debated) issue. We used wing and head geometric morphometrics to investigate the taxonomic status of 230 adult specimens representing all four 'R. prolixus group' species (19 populations from palm trees, domiciles, and reference laboratory colonies). Discriminant analyses of shape variation allowed for an almost perfect reclassification of individuals to their putative species. Shape patterning revealed no consistent differences between most specimens collected inside houses in central Brazil and R. neglectus, and showed that R. robustus and R. neglectus occur sympatrically (and fly into houses) in southern Amazonia. Furthermore, all Brazilian specimens clearly differed from our reference R. prolixus population. Using geometric morphometrics, we confidently ascribed individual triatomines to their species within the problematic 'R. prolixus group', illustrating the potential value of this approach in entomological surveillance. Our results strongly support the idea that R. neglectus, and not R. prolixus, is the species invading houses in central Brazil. 相似文献
134.
135.
Margarida Cortez Joana Ferreira Leonor Lopes Manuel Pereira-Barbosa Manuel Bicho 《Human immunology》2013
Aim
The aim of the this study was to analyse if there is an association between angiotensin converting enzyme (ACE) insertion/deletion (I/D) polymorphism (287 base pairs, on chromosome 17q23, intron 16) with asthma severity . ACE plays a vital role in the renin-angiotensin-system (RAS) which regulates blood pressure by converting angiotensin I into a powerfull vasoconstrictor angiotensin II and could also have a role in bronchoconstriction and airway remodeling in asthmatic disease.Methods
Asthmatic patients: n = 22;were compared with a control group of n = 206 healthy blood donors. The insertion/deletion (I/D) polymorphism was determined by PCR- Polymerase chain reaction. Control of asthma assessed by validated instrument (ACQ7 and PAQLQ). Statistical analysis was performed with PASW 18, establishing a significance level of p< 0.05. All patients signed an informed consent.Results
The mean age of the 22 asthmatics was 42.86 ± 20.8 years; 9 females and 13 males; all caucasians; 20 atopic and 2 nonatopic. The mean age of the control-group (n = 206) was 41.05 ± 11.85 years; 70 females and 136 males. In asthmatics the frequencies of the D- Allele (ACE-D) is 0.591 and of the IAllele (ACE-I) is 0.409; in controls: 0.675 and 0.325 respectively. There is no statistical differences between these groups (p = 0.340). Genotypes in the asthmatics- DD: 45.4%; ID: 27.3%; II: 27,3%; in control group- DD:48.1%; ID:38.8%; II: 13.1%. There is no statistical differences between these groups (p = 0,175). In asthmatics, there is no statistical differences in genotype frequencies (p > 0.05) between : atopics and non atopics; controlled and uncontrolled asthma; males and females; and in the different age-groups.Conclusions
The role of ACE insertion/deletion (I/D) polymorphism, in asthmatic patients is a controversy risk factor to the severity of asthma, but we think that we need a larger sample to infer about its role in remodeling, vascular tonus and bronchoconstriction. 相似文献136.
Laura Cerqueira Ricardo M. Fernandes Rui M. Ferreira Mónica Oleastro Fátima Carneiro Catarina Brand?o Pedro Pimentel-Nunes Mário Dinis-Ribeiro Céu Figueiredo Charles W. Keevil Maria J. Vieira Nuno F. Azevedo 《Journal of clinical microbiology》2013,51(6):1887-1893
Here, we evaluated a previously established peptide nucleic acid-fluorescence in situ hybridization (PNA-FISH) method as a new diagnostic test for Helicobacter pylori clarithromycin resistance detection in paraffin-embedded gastric biopsy specimens. Both a retrospective study and a prospective cohort study were conducted to evaluate the specificity and sensitivity of a PNA-FISH method to determine H. pylori clarithromycin resistance. In the retrospective study (n = 30 patients), full agreement between PNA-FISH and PCR-sequencing was observed. Compared to the reference method (culture followed by Etest), the specificity and sensitivity of PNA-FISH were 90.9% (95% confidence interval [CI], 57.1% to 99.5%) and 84.2% (95% CI, 59.5% to 95.8%), respectively. In the prospective cohort (n = 93 patients), 21 cases were positive by culture. For the patients harboring clarithromycin-resistant H. pylori, the method showed sensitivity of 80.0% (95% CI, 29.9% to 98.9%) and specificity of 93.8% (95% CI, 67.7% to 99.7%). These values likely represent underestimations, as some of the discrepant results corresponded to patients infected by more than one strain. PNA-FISH appears to be a simple, quick, and accurate method for detecting H. pylori clarithromycin resistance in paraffin-embedded biopsy specimens. It is also the only one of the methods assessed here that allows direct and specific visualization of this microorganism within the biopsy specimens, a characteristic that allowed the observation that cells of different H. pylori strains can subsist in very close proximity in the stomach. 相似文献
137.
Nilson Vieira Pinto Benildo Sousa Cavada Lucas Ferreira Brito Ronniery Ilario Pereira Mayara Torquato Lima da Silva Rondinelle Ribeiro Castro Alana de Freitas Pires Ana Maria Sampaio Assreuy 《Inflammation》2013,36(3):713-722
The anti-inflammatory activity of Canavalia seed lectins (Canavalia gladiata [CGL], Canavalia maritima [ConM] and Canavalia brasiliensis [ConBr]) was evaluated by intravenous administration in rats. In non-sensitized rats, cellular edema elicited by carrageenan was reduced (45–51 %) by ConM and (44–59 %) by CGL. Osmotic edema elicited by dextran was reduced by ConM and CGL in 27 % and 29 %. ConM and CGL reduced the edema elicited by l-arginine in 53 % and that of prostaglandin E2 in 48 % and 36 %. Leukocyte migration elicited by carrageenan was reduced in 49 % by ConM and in 55 % by CGL (attenuated in 4× by glucose) and peritoneal TNF-α content in 82 %. In rats sensitized, ConM inhibited the paw edema and leukocyte migration elicited by ovalbumin in 34 % and 70 %. ConM and CGL are anti-inflammatory, mainly in cellular events mediated by prostaglandin E2, nitric oxide and TNF-α in non-sensitized rats. However, only ConM is anti-inflammatory in sensitized rats. CGL effect involves the lectin domain. 相似文献
138.
Bezagio Renata Coltro Colli Cristiane Maria Romera Liara Izabela Lopes de Almeida Caroline Rodrigues Ferreira Érika Cristina Gomes Mônica Lúcia 《European journal of clinical microbiology & infectious diseases》2021,40(12):2633-2638
European Journal of Clinical Microbiology & Infectious Diseases - In order to improve the diagnosis of giardiasis, fecal samples (high/medium/low concentration of cysts) were processed by the... 相似文献
139.
Camila P. Almeida Camila O. Silveira Enio F. Ferreira Marcia C. Ferreira Gabriella G. Oliveira Emerson S. Veloso Felipe H.S. Silva Santuza S. Coelho Leonardo M. Moraes Fernando M. Reis Helen L. Del Puerto 《Acta histochemica》2021,123(2):151670
Apoptosis regulation in luteinized granulosa cells (LGC) during assisted reproduction procedures is still controversial. Caspase-3 is a major apoptosis mediator encoded by CASP3 and formed through cleavage of its precursor pro-caspase-3. The aim of this study was to investigate the expression patterns of pro-caspase-3 (mRNA and protein) and cleaved caspase-3 in human LGC. Thirty-five women undergoing controlled ovarian stimulation for in vitro fertilization were prospectively enrolled in the study. LGC were isolated from follicular fluid during oocyte pickup and evaluated by immunocytochemistry for pro-caspase-3 and cleaved caspase-3, and by real-time PCR for CASP3 mRNA expression. We found a positive staining of pro-caspase-3 in 77 % of the LGC (95 % confidence interval [CI] 60%–84%), whereas cleaved caspase-3 was found in only 4% of the cells (95 % CI 3%–6%). The abundance of cells expressing pro-caspase-3 was independent from CASP3 mRNA levels (r = 0.24, p = 0.255) and did not correlate with the amount of cleaved caspase-3 (r = -0.24, p = 0.186). Multivariable logistic regression showed that pro-caspase-3 positivity was not influenced by clinical characteristics such as age, cause or length of infertility, antral follicle count or hormonal drugs used to induce ovulation. These findings suggest that pro-caspase-3 is constitutively expressed in LGC, allowing quick cleavage into active caspase-3 and apoptosis triggering whenever needed in the course of gonadotropin-induced follicular development. 相似文献
140.