全文获取类型
收费全文 | 33194篇 |
免费 | 3726篇 |
国内免费 | 998篇 |
专业分类
耳鼻咽喉 | 399篇 |
儿科学 | 387篇 |
妇产科学 | 398篇 |
基础医学 | 1994篇 |
口腔科学 | 9712篇 |
临床医学 | 2310篇 |
内科学 | 2505篇 |
皮肤病学 | 613篇 |
神经病学 | 698篇 |
特种医学 | 442篇 |
外国民族医学 | 1篇 |
外科学 | 1837篇 |
综合类 | 3858篇 |
现状与发展 | 4篇 |
预防医学 | 1560篇 |
眼科学 | 310篇 |
药学 | 6401篇 |
34篇 | |
中国医学 | 2827篇 |
肿瘤学 | 1628篇 |
出版年
2024年 | 80篇 |
2023年 | 626篇 |
2022年 | 711篇 |
2021年 | 1292篇 |
2020年 | 1437篇 |
2019年 | 1405篇 |
2018年 | 1348篇 |
2017年 | 1299篇 |
2016年 | 1359篇 |
2015年 | 1324篇 |
2014年 | 2030篇 |
2013年 | 2536篇 |
2012年 | 1932篇 |
2011年 | 2026篇 |
2010年 | 1596篇 |
2009年 | 1435篇 |
2008年 | 1397篇 |
2007年 | 1461篇 |
2006年 | 1357篇 |
2005年 | 1308篇 |
2004年 | 1126篇 |
2003年 | 1040篇 |
2002年 | 894篇 |
2001年 | 811篇 |
2000年 | 666篇 |
1999年 | 577篇 |
1998年 | 489篇 |
1997年 | 499篇 |
1996年 | 411篇 |
1995年 | 384篇 |
1994年 | 343篇 |
1993年 | 252篇 |
1992年 | 291篇 |
1991年 | 215篇 |
1990年 | 203篇 |
1989年 | 211篇 |
1988年 | 177篇 |
1987年 | 157篇 |
1986年 | 128篇 |
1985年 | 158篇 |
1984年 | 149篇 |
1983年 | 107篇 |
1982年 | 126篇 |
1981年 | 116篇 |
1980年 | 85篇 |
1979年 | 67篇 |
1978年 | 55篇 |
1977年 | 67篇 |
1976年 | 45篇 |
1975年 | 38篇 |
排序方式: 共有10000条查询结果,搜索用时 20 毫秒
81.
Fix Joseph A. Alexander Jose Cortese Margot Engle Karen Leppert Paula Repta A. J. 《Pharmaceutical research》1990,7(4):384-387
Short-chain alkyl esters of L-dopa were administered to rats and mice via oral and rectal routes. Plasma L-dopa esters and L-dopa were determined in the systemic and portal circulation by HPLC. A comparison of isopropyl, butyl, and 4-hydroxybutyl esters of L-dopa demonstrated significantly higher levels of the esters in both systemic and portal blood samples following rectal administration than following oral administration. In most cases, oral administration resulted in nondetectable (<0.01 µg/ml) levels of the esters in plasma. Correspondingly, the plasma levels of L-dopa itself were consistently higher following rectal administration. At very high oral doses (500 mg L-dopa equivalents/kg body weight), systemic plasma levels of the butyl ester could be detected (1.25 µg/ml at 10 min), which might indicate saturation of the esterase activity of the small intestine. These studies indicate that the systemic availability of L-dopa from short-chain alkyl esters of L-dopa may be best optimized by rectal administration, which avoids the relatively high esterase activity characteristic of the small intestine. 相似文献
82.
Norethisterone enanthate (NET-En), an established intramuscular long-acting contraceptive agent, has previously been shown to be effective in inhibiting fertility in two rodent species even 4 days after oral ingestion. Pharmacokinetics of NET and NET-En were studied after oral and intramuscular doses in two animal species and a few women. The results suggest that the NET-En was absorbed within a day in all the species after oral dose. The estimates of relative bioavailability ranged from 13 to 51% in rabbits, monkeys, and women. The elimination half-life was 5–10 days. The presence of the active component, NET, in the circulation over the experimental period of 15 days suggests that NET-En could be useful as a long-acting oral pill. The suppression of progesterone levels during the luteal phase of menstrual cycle in women also supports this finding. 相似文献
83.
Anu Kilpi Alison M. Rich Yrjö T. Konttinen Peter C. Reade 《European journal of oral sciences》1996,104(3):278-284
Oral mucosal lichen planus (OMLP) is a well recognized mucosal disease with unknown etiology. Considerable controversy exists as to whether OMLP is intrinsically premalignant, or if the disorder facilitates the development of oral mucosal squamous cell carcinoma (OMSCC) by external factors. The aim of the present study was to investigate the expression of c-erbB-2 protein in the keratinocytes of initial biopsies of oral mucosal disorders diagnosed as OMLP with no evidence of epithelial dysplasia. and to compare the results with the expression of c-erbB-2 protein in subsequent biopsies obtained from the same patients. These results were compared with the findings from control groups (patients with dysplasia with no evidence of OMLP, patients with OMSCC with no evidence of OMLP and normal oral mucosa). The expression of the c-erbB-2 protein was evaluated by immunohistochemical staining of the gene product with the avidin-biotin-complex method using paraffin-embedded tissue sections. Five of the initial biopsies from patients with OMLP expressed the c-erhB-2 protein and one did not. None of the OMLP cases that subsequently showed evidence of dysplasia expressed the c-erhB-2 protein, and of the three OMSCC specimens from the patients with OMLP. two were negative and one expressed c-erbB-2 protein. The specimens from the control groups all expressed the c-erhB-2 protein. The results indicated the probability of the absence of c-erbB-2 staining being an indication of a potential for neoplastic transformation in OMLP with dysplastic changes. 相似文献
84.
Effect of Prevention and Treatment of Murine Acute Viral Myocarditisand Protection of Lymphoid Organ Atrophy withXinkang Oral Liquid (心康口服液) 下载免费PDF全文
Ithasbeenestablishedthatcoxsackievirusisthepredominantcauseofviralmyocarditisinhuman(1) ,whichisacommondiseaseseriouslyendangerhea 相似文献
85.
The suicide substrate reaction is a model for certain enzyme-inhibitingdrugs. This reaction system is examined assuming that the substratediffuses freely while the enzyme remains fixed. Two sets ofinitial and boundary conditions are examined: one modellingan instantaneous point source, akin to an injection of substrate,the other, a continuous point source, akin to a continuing influx,or intravenous drip, of substrate. The quasi-steady-state assumptionis applied to obtain analytical solutions for a limited parameterspace. Finally, further applications of numerical and analyticalexperimentation on pharmaceutical mechanisms are described. 相似文献
86.
87.
Christopher J. Holmgren Esmonde F. Corbet L. P. Lim 《Community dentistry and oral epidemiology》1994,22(5):396-402
Abstract The aim of this study was to describe the periodontal conditions in 372 35–44-yr-old and 537 noninstitutionalized 65–74-yr-old Hong Kong Chinese who were examined clinically for loss of attachment, recession, probing depth, calculus, and bleeding after probing. Community Periodontal Index (CPI) data and treatment need indications were compiled from index teeth or their substitutes. The prevalence of loss of attachment varied considerably in both cohorts according to the definition of the threshold (≥6, ≥9, and ≥12 mm, respectively). The mean numbers of teeth with loss of attachment at the ≥6-mm threshold and at higher thresholds were small. In both age cohorts, about one-fifth of subjects had probing depths ≥6-mm, while al the ≥9-mm threshold only 2–3% were so affected. Although recession was an important component of loss of attachment in the younger cohort, in the older cohort the prevalence and extent of recession were greater than for probing depths at thresholds ≥4 mm. All subjects had one or more teeth with calculus, bleeding, or both, most teeth being so affected. Eighty-four of the 537 65–74-yr-old subjects were excluded either because of edentulousness or because extractions indicated for the remaining teeth would have rendered the subjects edentulous. The distribution of subjects according to their highest CPI score was remarkably similar for the two cohorts. No subjects in either age group were assessed as “healthy” (CPI code 0) or had “bleeding only” (code 1) as their highest score. While most subjects scored CPI code 2 or 3 us their highest score, only 17% of the younger and 15% of the older cohort scored Community Periodontal Index of Treatment Needs (CPITN) code 4. Differences in the mean number of sextants affected by CPI codes between the two cohorts were mainly due to a greater number of excluded sextants in the older cohort. CPI findings for 35–44-yr-olds differed little from those reported in 1984. 相似文献
88.
The MIC values of the antifungal drug ketoconazole were evaluated on 66 Candida albicans strains. These strains were isolated from 26 HIV-1 infected patients with oral recurrent candidosis. Each episode of oral candidosis observed in these patients was orally treated with ketoconazole (200 mg/day) until the clinical disappearance of the lesions. The most frequent MIC values were 20 micrograms/ml and 10 micrograms/ml, observed in 37 and 19 isolates respectively. Only strains from five patients showed changes in their susceptibility to ketoconazole. This fact could indicate that a different strain causes the subsequent reappearance of the oral lesions, rather than the drug selecting resistant fungal strains. Our results stress the role of host characteristics in the occurrence of candidal infections, pointing to the progressing failure of the immunological response as the most important factor responsible for the recurrence of oral candidosis during HIV-1 infection. 相似文献
89.
长泰乐生物保健口服液是一种新型腹泻治疗药物,用该药治疗感染性腹泻45例,与用氟哌酸治疗的对照组比较,结果表明疗效相近,且比后者使用安全。我们认为该药可代替抗生素用于治疗感染性腹泻轻、中型患者,尤其适用于老年、孕妇和儿童。对非感染性腹泻有良好的治疗前景。 相似文献
90.
John K. Brooks Claire O. Leonard Peter J. Coccaro 《American journal of medical genetics. Part A》1992,43(3):595-601
We studied a new case of the G (Opitz BBB/G) syndrome in a 12-year-old boy. Several relatives had partial manifestations of the disorder. A comprehensive dental evaluation of the propositus was conducted; included is, to our knowledge, the first published cephalometric analysis of a G syndrome patient. We reviewed 139 cases of the G syndrome; 48 of them had at least one oral abnormality. These included clefting, micrognathia, ankyloglossia, and high-arched palate. Male G syndrome patients are more likely to have oral anomalies than affected females. © 1992 Wiley-Liss, Inc. 相似文献