全文获取类型
收费全文 | 5744篇 |
免费 | 566篇 |
国内免费 | 33篇 |
专业分类
耳鼻咽喉 | 65篇 |
儿科学 | 198篇 |
妇产科学 | 155篇 |
基础医学 | 594篇 |
口腔科学 | 227篇 |
临床医学 | 579篇 |
内科学 | 1530篇 |
皮肤病学 | 133篇 |
神经病学 | 466篇 |
特种医学 | 459篇 |
外科学 | 754篇 |
综合类 | 26篇 |
预防医学 | 575篇 |
眼科学 | 46篇 |
药学 | 261篇 |
中国医学 | 27篇 |
肿瘤学 | 248篇 |
出版年
2023年 | 65篇 |
2022年 | 51篇 |
2021年 | 126篇 |
2020年 | 92篇 |
2019年 | 142篇 |
2018年 | 194篇 |
2017年 | 118篇 |
2016年 | 148篇 |
2015年 | 161篇 |
2014年 | 246篇 |
2013年 | 300篇 |
2012年 | 278篇 |
2011年 | 347篇 |
2010年 | 239篇 |
2009年 | 237篇 |
2008年 | 272篇 |
2007年 | 293篇 |
2006年 | 294篇 |
2005年 | 264篇 |
2004年 | 232篇 |
2003年 | 159篇 |
2002年 | 169篇 |
2001年 | 150篇 |
2000年 | 191篇 |
1999年 | 139篇 |
1998年 | 101篇 |
1997年 | 111篇 |
1996年 | 114篇 |
1995年 | 81篇 |
1994年 | 86篇 |
1993年 | 67篇 |
1992年 | 64篇 |
1991年 | 59篇 |
1990年 | 86篇 |
1989年 | 91篇 |
1988年 | 65篇 |
1987年 | 55篇 |
1986年 | 70篇 |
1985年 | 64篇 |
1984年 | 27篇 |
1983年 | 25篇 |
1982年 | 31篇 |
1981年 | 32篇 |
1980年 | 23篇 |
1979年 | 27篇 |
1978年 | 17篇 |
1977年 | 18篇 |
1976年 | 27篇 |
1975年 | 20篇 |
1974年 | 13篇 |
排序方式: 共有6343条查询结果,搜索用时 15 毫秒
71.
72.
Dayana A. Delgado Meytal Chernoff Lei Huang Lin Tong Lin Chen Farzana Jasmine Justin Shinkle Shelley A. Cole Karin Haack Jack Kent Jason Umans Lyle G. Best Heather Nelson Donald Vander Griend Joseph Graziano Muhammad G. Kibriya Ana Navas-Acien Margaret R. Karagas Habibul Ahsan Brandon L. Pierce 《Environmental health perspectives》2021,129(5)
73.
A technique for eliminating allele specific amplification failure during DNA amplification of heterozygous cells for preimplantation diagnosis 总被引:6,自引:5,他引:6
Advances in techniques of molecular biology have made possible the
amplification of specific genes from single cells. This has a major
clinical application in preimplantation diagnosis of monogenic disorders.
However, the incidence of allele specific amplification failure (allele
drop out) in heterozygous single cells can lead to misdiagnosis and the
transfer of affected embryos. Few studies have been done to investigate the
actual cause of allele drop out, although some investigators have succeeded
in reducing but not eliminating it. Here we report the efficiency of
amplifying both alleles in heterozygous cells lysed according to two
different protocols. A total of 177 heterozygous cells from carriers of
cystic fibrosis (CF) and haemoglobin C (HbC) were lysed using two different
lysis buffers. Interestingly none of the cells that were lysed with sodium
dodecyl sulphate/proteinase K showed any example of allele specific
amplification failure whereas in those lysed by KOH/dithiothreitol it was
present in 17.6 and 4.7% of the CF and HbC cells respectively. Our results
suggest that the phenomenon of allele specific amplification failure is at
least in part dependent on the lysis buffer used.
相似文献
74.
Salcedo M Taja L Utrera D Chávez P Hidalgo A Pérez C Benítez L Castañeda C Delgado R Gariglio P 《International journal of experimental pathology》2002,83(6):275-286
The role of tumour suppressor genes in the development of human cancers has been studied extensively. In viral carcinogenesis, the inactivation of suppressor proteins such as retinoblastoma (pRb) and p53, and cellular oncogenes overexpression, such as c-myc, has been the subject of a number of investigations. In uterine-cervix carcinomas, where high-risk human papillomavirus (HPV) plays an important role, pRb and p53 are inactivated by E7 and E6 viral oncoproteins, respectively. However, little is known about the in situ expression of some of these proteins in pre-malignant and malignant cervical tissues. On the other hand, it has also been demonstrated that c-myc is involved in cervical carcinogenesis, and that pRb participates in the control of c-myc gene expression. By using immunostaining techniques, we investigated pRb immunodetection pattern in normal tissues, squamous intraepithelial lesions (SILs) and invasive carcinomas from the uterine cervix. Our data show low pRb detection in both normal cervical tissue and invasive lesions, but a higher expression in SILs. C-Myc protein was observed in most of the cellular nuclei of the invasive lesions, while in SILs was low. These findings indicate a heterogeneous pRb immunostaining during the different stages of cervical carcinogenesis, and suggest that this staining pattern could be a common feature implicated in the pathogenesis of uterine-cervix carcinoma. 相似文献
75.
The incomplete inactivation of Fgf8 in the limb ectoderm affects the morphogenesis of the anterior autopod through BMP-mediated cell death. 总被引:1,自引:0,他引:1
Irene Delgado Elena Domínguez-Frutos Thomas Schimmang Maria A Ros 《Developmental dynamics》2008,237(3):649-658
Here we analyze limb development after the conditional inactivation of Fgf8 from the epiblast, using the previously described MORE (Mox2Cre) line. This line drives variable mosaic recombination of a floxed Fgf8 allele, resulting in a small proportion of AER cells that maintain Fgf8 expression. The phenotype of Mox2Cre;Fgf8 limbs is most similar to that of Msx2Cre;Fgf8 forelimbs, indicating that a small but durable expression of FGF8 is equivalent to an early normal, but transitory, expression. This functional equivalence likely relies on the subsequent Fgf4 upregulation that buffers the differences in the pattern of Fgf8 expression between the two conditional mutants. The molecular analysis of Mox2Cre;Fgf8 limbs shows that, despite Fgf4 upregulation, they develop under reduced FGF signaling. These limbs also exhibit an abnormal area of cell death at the anterior forelimb autopod, overlapping with an ectopic domain of Bmp7 expression, which can explain the abnormal morphogenesis of the anterior autopod. 相似文献
76.
Joanna Luczkowiak Gonzalo Rivas Nuria Labiod Fátima Lasala Marta Rolo Jaime Lora-Tamayo Mikel Mancheno-Losa David Rial-Crestelo Alfredo Pérez-Rivilla María Dolores Folgueira Rafael Delgado 《Journal of medical virology》2023,95(1):e28268
We have measured the humoral response to messenger RNA (mRNA) vaccines in COVID-19 naïve and convalescent individuals. Third doses of mRNA COVID-19 vaccines induced a significant increase in potency and breadth of neutralization against SARS-CoV-2 variants of concern (VoC) including Omicron subvariants BA.1, BA.2, and BA.2.12.1, that were cross-neutralized at comparable levels and less for BA.4/5. This booster effect was especially important in naïve individuals that only after the third dose achieved a level that was comparable with that of vaccinated COVID-19 convalescents except for BA.4/5. Avidity of RBD-binding antibodies was also significantly increased in naïve individuals after the third dose, indicating an association between affinity maturation and cross neutralization of VoC. These results suggest that at least three antigenic stimuli by infection or vaccination with ancestral SARS-CoV-2 sequences are required to induce high avidity cross-neutralizing antibodies. Nevertheless, the circulation of new subvariants such as BA.4/5 with partial resistance to neutralization will have to be closely monitored and eventually consider for future vaccine developments. 相似文献
77.
Palmares J Castro-Correia J Coutinho MF Araújo D Delgado L 《Ocular immunology and inflammation》1995,3(2):99-106
The authors review the visual prognosis of 44 patients with Beh?et's disease referred to the Ophthalmology and Rheumatology Departments (Hospital S. Jo?o-one of the two major referral centers in Northern Portugal), due to ocular complaints or for routine examination, in the last ten years. All fulfilled the clinical criteria for diagnosis of Beh?et's disease. Twenty-six were male and 18 female, with mean age 37 years (range 23-66). The mean evolution time since the first clinical manifestations was ten years (range 1-21). Aphthous stomatitis (100%) and genital ulcers (77.3%) were the initial manifestations preceding eye involvement. HLA-B(51)(5) was present in 27 of 36 typed patients (75%). Ocular manifestations were present in 33 patients (75%)-22 patients with panuveitis, eight with hypopyon, four with chronic anterior uveitis and three with episcleritis. Mean age of onset of ocular complications was 32 years (range 20-54). Retinal vaso-occlusive vasculitis was diagnosed in 26 patients (22 with panuveitis and four with posterior uveitis). To prevent ocular relapses, all needed immunosuppression with corticosteroids (drops, depo or systemic), combined with cyclosporine A (CsA) (5 mg/kg/day) in 13 patients and with chlorambucil or cyclophosphamide in six patients, when sight threatening uveitis had previously been refractory to treatment with systemic steroids. The 13 patients under CsA were observed for a period ranging from eight months to five years. Lowdose CsA was found to abrogate the intraocular inflammation, was well tolerated and had no major adverse effects. Regardless of the type of treatment, 21% (14/66) of the eyes lost useful vision five to ten years after initial diagnosis. 相似文献
78.
Case-control analysis of clostridium difficile-associated diarrhea on a gynecologic oncology service
下载免费PDF全文
![点击此处可从《Infectious diseases in obstetrics and gynecology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Waggoner SE Barter J Delgado G Barnes W 《Infectious diseases in obstetrics and gynecology》1994,2(4):154-161
Objective: The incidence, morbidity, and risk factors associated with Clostridium difficile-associated diarrhea (CDAD) were studied in a group of gynecologic oncology patients.Methods: A case-control analysis of gynecologic oncology patients with CDAD was carried out from August 1986 through January 1989 in a university medical center.Results: One hundred twenty-three stool samples were tested for C. difficile using the CDT latex agglutination test (Marion Diagnostics, Kansas City, MO). Thirty episodes of CDAD developed in 23 patients. From August 1986 through July 1988, the incidence was stable at 1.5 episodes/100 admissions. From August 1988 through January 1989, the incidence increased to 9.9 episodes/100 admissions (P = 0.005). Compared with patients with nonspecific antibiotic-associated diarrhea, the study patients were hospitalized longer prior to the development of symptoms (mean 15.2 vs. 9.2 days, P = 0.006) and were admitted more frequently with diarrhea (37% vs. 11%, P = 0.015). The rates of surgery, chemotherapy, and radiation therapy were similar. Fever (57% vs. 14%, P < 0.001), abdominal pain (40% vs. 6%, P < 0.001), bloody stools (27% vs. 3%, P = 0.006), and leukocytosis (64% vs. 26%, P = 0.011) were more common among the study cases. The duration, indication, and number of antibiotics administered were similar, though once started, the mean time to symptoms was longer in the study cases (13.7 vs. 6.1 days, P = 0.004). Seven relapses, 1 death, and 1 unplanned colostomy occurred among women with CDAD.Conclusions: C. difficile is a serious cause of nosocomial morbidity in gynecologic oncology patients. Diarrhea developing after antibiotic exposure is more likely to be associated with C. difficile in patients whose symptoms develop several days after completing antibiotics and in patients with a history of CDAD. 相似文献
79.
L Valdés M G Guzmán G Kourí J Delgado I Carbonell M V Cabrera D Rosario S Vázquez 《Pan American journal of public health》1999,6(1):16-25
A dengue epidemic that Cuba reported in 1997 registered more than 500,000 cases of dengue fever produced by viral serotype 1. In 1981, there was an epidemic of dengue hemorrhagic fever produced by serotype 2 of the virus. This time 344,203 clinical cases were reported, 10,312 of which were severe cases of hemorrhagic fever that led to 158 fatalities (101 of them among children). The reintroduction of dengue, and specifically of dengue viral serotype 2 (Jamaica genotype), was quickly detected in January 1997 through an active surveillance system with laboratory confirmation of cases in the municipality of Santiago de Cuba, in the province of the same name. The main epidemiological features of this outbreak are reported in this paper. A total of 3,012 cases were reported and serologically confirmed. These included 205 cases classified as dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS), 12 of which were case fatalities (all among adults). Secondary infection with dengue virus was one of the most important risk factors for DHF/DSS. Ninety-eight percent of the DHF/DSS cases and 92% of the fatal cases had contracted a secondary infection. It was the first time dengue hemorrhagic fever was documented as a secondary infection 16 to 20 years after initial infection. Belonging to the white racial group was another important risk factor for DHF/DSS, as had been observed during the 1981 epidemic. During the most recent epidemic it was demonstrated that the so called "fever alert" is not useful for early detection of an epidemic. Measures taken by the country's public health officials prevented spread of the epidemic to other municipalities plagued by Aedes aegypti. 相似文献
80.