全文获取类型
收费全文 | 13750篇 |
免费 | 767篇 |
国内免费 | 56篇 |
专业分类
耳鼻咽喉 | 98篇 |
儿科学 | 522篇 |
妇产科学 | 327篇 |
基础医学 | 1978篇 |
口腔科学 | 302篇 |
临床医学 | 1423篇 |
内科学 | 2752篇 |
皮肤病学 | 247篇 |
神经病学 | 1854篇 |
特种医学 | 454篇 |
外科学 | 1233篇 |
综合类 | 77篇 |
一般理论 | 9篇 |
预防医学 | 1065篇 |
眼科学 | 221篇 |
药学 | 940篇 |
中国医学 | 51篇 |
肿瘤学 | 1020篇 |
出版年
2023年 | 108篇 |
2022年 | 233篇 |
2021年 | 387篇 |
2020年 | 254篇 |
2019年 | 327篇 |
2018年 | 388篇 |
2017年 | 273篇 |
2016年 | 316篇 |
2015年 | 408篇 |
2014年 | 525篇 |
2013年 | 747篇 |
2012年 | 1062篇 |
2011年 | 1112篇 |
2010年 | 584篇 |
2009年 | 536篇 |
2008年 | 875篇 |
2007年 | 939篇 |
2006年 | 861篇 |
2005年 | 840篇 |
2004年 | 735篇 |
2003年 | 725篇 |
2002年 | 669篇 |
2001年 | 140篇 |
2000年 | 118篇 |
1999年 | 142篇 |
1998年 | 142篇 |
1997年 | 117篇 |
1996年 | 90篇 |
1995年 | 86篇 |
1994年 | 65篇 |
1993年 | 52篇 |
1992年 | 63篇 |
1991年 | 51篇 |
1990年 | 38篇 |
1989年 | 34篇 |
1988年 | 36篇 |
1987年 | 25篇 |
1986年 | 41篇 |
1985年 | 33篇 |
1984年 | 39篇 |
1983年 | 44篇 |
1982年 | 42篇 |
1981年 | 44篇 |
1980年 | 35篇 |
1979年 | 30篇 |
1978年 | 22篇 |
1977年 | 14篇 |
1976年 | 12篇 |
1975年 | 18篇 |
1972年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Flexible Sigmoidoscopy Screening in an Industrial Setting 总被引:1,自引:0,他引:1
Benjamin Krevsky M.D. M.P.H. F.A.C.G. Tomasz Niewiarowski M.D. Rita League R.N. Harold Herman M.D. Lisa Matz Robert S. Fisher M.D. F.A.C.G. 《The American journal of gastroenterology》1992,87(12):1759-1762
Little is known about the yield of colorectal cancer screening programs in an industrial setting. We therefore established a flexible sigmoidoscopy screening program at a chemical manufacturing plant and offered testing to all employees over the age of 40. After a Fleet enema preparation had been administered, a digital rectal examination and sigmoidoscopy were performed on each volunteer worker in the medical office of the plant. The plant had an average census of about 650 workers; 202 were screened during a 2-yr period. The mean (+/- SEM) age of participants was 52 +/- 0.4. Sixty-four employees had polyps (31.7%); data on follow-up colonoscopy were available in 69%. Colonoscopy revealed adenomatous polyps in 23 workers (53.5%), hyperplastic polyps in 10 (23%), and no evidence of neoplasia in 10 (23%). Seven workers did not arrange for follow-up colonoscopy and 12 individuals could not be contacted. No cancers were detected. In the 40- to 50-yr age group, polyps were detected in 19.5% of employees (25% adenomatous). Incidental findings were common, and included prostatic nodules, hemorrhoids, diverticulosis, and proctitis, among others. We conclude that screening sigmoidoscopy can be conveniently and economically performed at the workplace, with a high yield and good worker acceptance. The high yield suggests a possible association between polyp formation and work in a chemical plant. The finding of adenomatous polyps in the younger patients suggests that the threshold for flexible sigmoidoscopy at age 50 needs to be reassessed. 相似文献
22.
23.
24.
Joaquim Ferreira MD João Maia Silva MD Rita Freire BS João Pignatelli MD Leonor Correia Guedes MD Alexandra Feijó MD Mário Miguel Rosa MD Miguel Coelho MD João Costa MD Ana Noronha BS Russell Hewett MD A. Marques Gomes PhD J.L. Cirne de Castro MD Olivier Rascol PhD Cristina Sampaio PhD 《Movement disorders》2007,22(10):1471-1475
Our objective was to evaluate the frequency of neoplastic and preneoplastic skin lesions in Parkinson's disease (PD) patients when compared with an aged-matched population. We performed a cross-sectional survey in PD patients and in an age-matched control group. Patients and controls were examined by a movement disorder specialist and a dermatologist. 150 PD patients and 146 controls were included. Thirty-five PD patients (23.3%) presented skin lesions that could be classified as neoplastic or preneoplastic vs. 20 subjects in the control group (13.7%) (OR 95%, CI 1.92 [1.05, 3.51]). However, this difference lost statistical significance when adjusted for gender (recruitment of controls was matched just for age with an over representation of males in the PD group). Twenty-nine PD patients (19%) presented actinic keratosis and basal cell carcinoma was diagnosed in 4 patients (3%). Although nonconclusive, our results are in agreement with previous studies suggesting an increased risk of skin cancer in PD patients. The frequency of actinic keratosis in PD patients and the associated risk to develop melanoma recommends its screening in future epidemiological studies. 相似文献
25.
Rita M. Kesteven 《Canadian Medical Association journal》1992,146(11):1899-1900
26.
S Amerini A Rubino L Mantelli S Filippi F Ledda 《European journal of pharmacology》1992,216(3):445-448
The role of pertussis toxin-sensitive G proteins on the alpha 2-adrenoceptor and mu-opioid receptor-mediated inhibition of the efferent function of capsaicin-sensitive neurones was investigated in guinea-pig atria pretreated with guanethidine. In the presence of atropine, CGP 20712A (2-hydroxy-5-(2-[hydroxy-3-(4-[(1-methyl- 4-trifluormethyl)1H-imidazol-2-yl]-phenoxy)propyl]aminoethoxyl+ ++)-benzamide) and prazosin, [D-Ala2,NMe-Phe4,Gly5-ol]enkephalin (DAGO, 0.1-3 microM) and 2-amino-6-allyl-5,6,7,8-tetrahydro-4H-thiazolo(4,5-d)azepine (BHT 920, 0.01-1 microM) reduced the positive inotropic effect induced by transmural stimulation of preparations obtained from control and from pertussis toxin-treated animals. These results suggest that pertussis toxin-sensitive G proteins are not involved in the inhibitory regulation of the efferent function of capsaicin-sensitive nerve terminals in cardiac tissue induced by alpha 2 and opioid receptor stimulation. 相似文献
27.
Eneida F. Vencio Rita C. Alencar Eduardo Zancope 《Journal of oral pathology & medicine》2007,36(2):120-122
A 13-year-old boy had complained of an asymptomatic swelling in the anterior maxilla for approximately 4 years. The patient reported no local trauma. The intra-oral examination revealed an exophytic lesion in the incisive papilla between the maxillary central and lateral incisor teeth. The radiographies detected no significant findings. Histopathologically, the lesion showed a dense fibrous tissue above the overlying mucosa. Bone ossification lay beneath a partially hypertrophic cartilage showing occasionally pleomorphic chondrocytes. Because of its microscopic aspects, heterotopic ossification may be mistaken for chondrosarcoma or other conditions involving periosteum, such as parosteal osteosarcoma. A case of heterotopic ossification in the anterior maxilla is presented, and clinicopathologic similarities with other osteochondromatous lesions are discussed. 相似文献
28.
Jeffrey F. Waring Rita Ciurlionis Robert A. Jolly Matthew Heindel Gerry Gagne Jane A. Fagerland Roger G. Ulrich 《Toxicology in vitro》2003,17(5-6):693-701
In vitro human hepatocyte cultures are a key tool in the investigation of xenobiotic toxicity and metabolism. In most in vitro hepatocyte studies, the cells are allowed to adhere to an extracellular matrix, such as collagen. Unfortunately, the ability of freshly isolated hepatocytes to adhere to collagen varies from donor to donor. We used microarray analysis to determine what gene expression differences exist between hepatocytes in suspension and hepatocytes attached to collagen. Results from different donors showed a considerable difference in gene expression patterns between the two hepatocyte populations. In addition, we also compared the gene expression profiles of hepatocytes in culture with liver tissue. The results showed that both hepatocytes in suspension and hepatocytes attached to collagen display significant gene expression differences compared with liver tissue. Finally, we show that both populations of hepatocytes are responsive to dexamethasone and regulate some of the same genes. Overall, our results suggest that either significant gene expression changes occur in isolated hepatocytes or that suspended and attached cells represent different populations of hepatocytes found in intact livers. 相似文献
29.
Rita Shiang Stephen G. Ryan Ya-Zhen Zhu Thomas J. Fielder Richard J. Allen Alan Fryer Sumimasa Yamashita Peter O'Connell John J. Wasmuth 《Annals of neurology》1995,38(1):85-91
Hyperekplexia is a rare, autosomal dominant neurological disorder characterized by hypertonia, especially in infancy, and by an exaggerated startle response. This disorder is caused by mutations in the ?1 subunit of the inhibitory glycine receptor (GLRA1). We previously reported two GLRA1 point mutations detected in 4 unrelated hyperekplexia families; both mutations were at nucleotide 1192 and resulted in the replacement of Arg271 by a glutamine (R271Q) in one case and a leucine (R271L) in the other. Here, 5 additional hyperekplexia families are shown to have the most common G-to-A transition mutation at nucleotide 1192. Haplotype analysis using polymorphisms within and close to the GLRA1 locus suggests that this mutation has arisen at least twice (and possibly four times). In 2 additional families, a third mutation is also presented that changes a tyrosine at amino acid 279 to a cysteine (Y279C). Five patients with atypical clinical features and equivocal or absent family history of hyperekplexia and 1 patient with a classical presentation but no family history are presented in whom a mutation in the GLRA1 gene was not detected. Thus, only clinically typical hyperekplexia appears to be consistently associated with GLRA1 mutations, and these affect a specific extracellular domain of the protein. 相似文献