全文获取类型
收费全文 | 3149篇 |
免费 | 228篇 |
国内免费 | 29篇 |
专业分类
耳鼻咽喉 | 28篇 |
儿科学 | 106篇 |
妇产科学 | 209篇 |
基础医学 | 360篇 |
口腔科学 | 66篇 |
临床医学 | 274篇 |
内科学 | 1092篇 |
皮肤病学 | 34篇 |
神经病学 | 231篇 |
特种医学 | 55篇 |
外科学 | 470篇 |
综合类 | 15篇 |
一般理论 | 2篇 |
预防医学 | 125篇 |
眼科学 | 54篇 |
药学 | 109篇 |
中国医学 | 3篇 |
肿瘤学 | 173篇 |
出版年
2023年 | 27篇 |
2022年 | 37篇 |
2021年 | 91篇 |
2020年 | 36篇 |
2019年 | 70篇 |
2018年 | 73篇 |
2017年 | 70篇 |
2016年 | 77篇 |
2015年 | 78篇 |
2014年 | 123篇 |
2013年 | 113篇 |
2012年 | 193篇 |
2011年 | 193篇 |
2010年 | 133篇 |
2009年 | 125篇 |
2008年 | 217篇 |
2007年 | 241篇 |
2006年 | 217篇 |
2005年 | 213篇 |
2004年 | 183篇 |
2003年 | 183篇 |
2002年 | 185篇 |
2001年 | 38篇 |
2000年 | 52篇 |
1999年 | 54篇 |
1998年 | 31篇 |
1997年 | 23篇 |
1996年 | 30篇 |
1995年 | 28篇 |
1994年 | 18篇 |
1993年 | 20篇 |
1992年 | 35篇 |
1991年 | 21篇 |
1990年 | 19篇 |
1989年 | 21篇 |
1988年 | 21篇 |
1987年 | 10篇 |
1986年 | 18篇 |
1985年 | 9篇 |
1984年 | 12篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 8篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1976年 | 6篇 |
1969年 | 6篇 |
1966年 | 3篇 |
排序方式: 共有3406条查询结果,搜索用时 15 毫秒
61.
IntroductionHypertension is a common major systemic disease and 1 of the most significant causes of mortality worldwide. Persistent hypertension is 1 of the risk factors for stroke, heart attack, heart failure, and arterial aneurysm and is a leading cause of chronic kidney failure. Common medications used to treat hypertension include beta blockers, angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, and calcium channel blockers. The purpose of this study was to assess the prevalence of periapical abscesses in patients with different types of hypertension conditions and to evaluate the effect of commonly used antihypertensive medications on the prevalence of periapical abscesses.MethodsThe integrated data of hospital patients were used. Data from the corresponding diagnosis codes for hypertensive conditions and periapical abscess were retrieved by searching the appropriate query in the database. The odds ratio (OR) of periapical abscesses, its association with hypertensive conditions, and the intake of 4 antihypertensive medications were calculated and analyzed statistically.ResultsThe prevalence of periapical abscesses in patients with hypertensive conditions was 1.2% compared with 0.558% in the general patient population of the hospital. The OR for the prevalence of periapical lesions in patients with hypertension was 2.32. For primary hypertension, the OR was 2.02; for hypertensive heart disease, the OR was 2.68; for hypertensive chronic kidney disease, the OR was 2.1; for hypertensive heart and chronic kidney diseases, the OR was 4.16; for secondary hypertension, the OR was 4.16; and for hypertension crisis, the OR was 5.64. For patients treated with beta blockers, the OR was 2.58; for patients treated with angiotensin-converting enzyme inhibitors, the OR was 2.73; for patients treated with angiotensin II receptor blockers, the OR was 1.93; and for patients treated with calcium channel blockers, the OR was 2.79. The differences were statistically significant (P < .0001). The OR for the prevalence of periapical abscesses in patients treated with angiotensin II receptor blockers was significantly lower than that of patients treated with either beta blockers or calcium channel blockers (P < .00001).ConclusionsUnder the conditions of this study, it appears that the prevalence of perapical abscesses is significantly higher in hypertensive patients. The prevalence of periapical abscesses is higher in patients with secondary hypertension than in those with primary hypertension. Angiotensin II receptor blockers may significantly lower the prevalence of periapical abscesses in hypertensive patients. 相似文献
62.
63.
64.
Loss of tumorigenicity of rat glioblastoma directed by episome-based antisense cDNA transcription of insulin-like growth factor I. 总被引:1,自引:1,他引:1 下载免费PDF全文
65.
Higher gastric mucin secretion and lower gastric acid output in first-degree relatives of gastric cancer patients 总被引:1,自引:0,他引:1
Vilkin A Levi Z Morgenstern S Shmuely H Gal E Hadad B Hardi B Niv Y 《Journal of clinical gastroenterology》2008,42(1):36-41
BACKGROUND: Patients infected by Helicobacter pylori who have first-degree relatives with gastric cancer have an 8-fold increased risk of developing gastric cancer themselves. Mucins are high-molecular-weight glycoproteins that play a cardinal role in the protective mechanism of the gastric epithelium. AIM: To study gastric acid and mucin secretion in dyspeptic patients with and without a family history of gastric cancer and H. pylori infection. MATERIALS AND METHODS: Twenty-six dyspeptic patients underwent esophago-gastro-duodenoscopy, gastric biopsies, and acid and mucin secretory tests. The sample was divided by family history of gastric cancer and H. pylori status. RESULTS: Patients who were infected by H. pylori had a significantly higher degree of inflammation than those who were not. H. pylori-positive patients with a positive family history had a lower basal and maximal gastric acid output than infected patients with no family history and noninfected controls, and a higher basal and maximal mucin output than infected patients with no family history. MUC5AC was the major mucin species expressed in gastric juice. CONCLUSIONS: In patients with relatives with gastric cancer, H. pylori infection is associated with a more severe inflammatory reaction consisting of decreased gastric acid secretion and increased mucin secretion. 相似文献
66.
Joseph Ilan Judith Ilan 《Proceedings of the National Academy of Sciences of the United States of America》1973,70(5):1355-1358
Treatment of insect polyribosomes with 1 M KCl released a messenger ribonucleoprotein with a pronounced 16S peak. Phenol extraction resulted in a defined peak of 10S RNA, which was judged as mRNA by the following criteria: it showed specificity for binding to ribosomes, and the formation of initiation complex was dependent on protein initiation factors, GTP, mRNA, and aminoacyl-tRNA. The complex directed protein synthesis upon the addition of elongation factors. mRNA was treated with phosphatase and phosphorylated at the 5'-end with [(32)P]cyanoethylphosphate. [(32)P]mRNA was digested by T1 ribonuclease to completion and chromatographed on DEAE-cellulose. The only fragment with (32)P was 15 nucleotides long; it was treated with pancreatic ribonuclease and fingerprinted. Fractions of AC, AAC, and AAAC were found. Initiation signal AUG or GUG in these mRNAs does not begin immediately at the 5'-end and may be at a distance greater than 15 nucleotides. Alkaline hydrolysis of mRNAs labeled in vivo with [(14)C]adenosine revealed Ap and pppAp. Alkaline hydrolysis of mRNA labeled with (32)P at the 5'-terminus resulted in pAp. Hence, these results suggest that in a heterogeneous population of mRNAs from insects, all start with A and have sequence homology at the 5'-termini. This sequence may reflect the signal for RNA polymerase on the gene or may promote the binding of mRNA to ribosomes. 相似文献
67.
Two 19 year old patients with juvenile chronic arthritis developed liver toxicity during treatment with sulphasalazine. A significant increase in the levels of liver enzymes in serum samples was noticed in relation to the initiation of treatment in one patient and to the increase in dose in the second. The enzymes returned to normal levels 14 days after the drug had been stopped. A rechallenge in one of the patients caused re-exacerbation. This is the first report of liver toxicity induced by sulphasalazine in juvenile chronic arthritis. As spontaneous liver involvement in juvenile chronic arthritis is not rare, the possibility of drug induced hepatitis should be recognised in these patients. 相似文献
68.
Israeli E Goldin E Shibolet O Klein A Hemed N Engelhardt D Rabbani E Ilan Y 《World journal of gastroenterology : WJG》2005,11(20):3105-3111
AIM: To evaluate safety and possible efficacy of induction of oral immune regulation using colitis extracted proteins(CEP) in Crohn‘s disease (CD) subjects.METHODS: Ten CDs were treated orally with autologous CEP thrice weekly for 16 wk. Subjects were monitored for CDAI and IBDQ. Immune modulatory effect was assessed by T-lymphocyte FACS analysis, CEP-specific IFNγ ELISPOT assay and cytokine levels.RESULTS: Induction of oral immune regulation significantly ameliorated disease activity. All (10/10) subjects had clinical response (CDAI≤70) and 7/10 achieved clinical remission (CDAI≤150). Significant increase in mean IBDQ score was noted (134±9vs 164±12). No treatment-related adverse events were noted. High levels of CEP-specific IFNγ spot forming colonies were detected in five subjects prior to treatment and in all five, a marked decrease was observed. The CD4+/CDS+ lymphocyte ratio and peripheral NKT cell numbers increased significantly, in 7/10 and in 5/10 subjects, respectively. Significant increase in serum IL-10 and IL-4 levels was observed in 7/10 subjects during treatment period.CONCLUSION: Immune regulation via oral administration of CEP is a safe and possibly effective treatment for subjects with moderate CD and may provide means of antigen-specific immune modulation. 相似文献
69.
Efrat Hadi MD Ilan Bruchim MD Ilana Helman MD Itshak Shehtman MD Rodica Stackievicz MD Ronnie Tepper MD Reli Hershkovitz MD 《Journal of clinical ultrasound : JCU》2015,43(1):59-63
Uterine lymphoma is rare and tends to be misdiagnosed due to lack of specific radiologic features. Few reports have been published on the sonographic characteristics of uterine lymphoma. We present a case report of uterine lymphoma manifested by a fast growing uterus and describe the sonographic findings. © 2014 Wiley Periodicals, Inc. J Clin Ultrasound, 43 :59–63, 2015 相似文献
70.
Marco A. O. Magalhaes Jonathan C. Irish Ilan Weinreb Bayardo Perez-Ordonez 《Head and neck pathology》2015,9(1):114-118
Adenosquamous carcinomas of the head and neck (ADSCs) are rare locally aggressive malignancies characterized by the presence of two distinctive components, a squamous cell carcinoma and an adenocarcinoma. The immunophenotype of the glandular component of ADSCs has only been rarely studied but has been reported as being positive for keratin 7 (CK7) and carcinoembryonic antigen (CEA) and negative for keratin 20 (CK20). Herein, we report a case of an ADSCs of the hypopharynx composed of a superficial squamous cell carcinoma and an adenocarcinoma with an intestinal phenotype. The patient was a 62 year-old male with a T2 N0 M0 squamous cell carcinoma (SCC) of uvula and palate and a T1 N0 M0 of right hypopharynx. The ADSCs of the hypopharynx was composed of a minimally invasive SCC and an adenocarcinoma with tubulo-glandular and cribriform architecture. The neoplastic glands were positive for CK7, CK20, CDX2, CEA and Villin. The patient underwent radiotherapy to both tumors and remains well with no evidence of recurrent disease 19 months after treatment. To the best of our knowledge, this is the first report of an ADSCs of the head and neck with an intestinal phenotype in its glandular component. 相似文献