全文获取类型
收费全文 | 5748篇 |
免费 | 248篇 |
国内免费 | 52篇 |
专业分类
耳鼻咽喉 | 25篇 |
儿科学 | 349篇 |
妇产科学 | 72篇 |
基础医学 | 654篇 |
口腔科学 | 163篇 |
临床医学 | 426篇 |
内科学 | 999篇 |
皮肤病学 | 257篇 |
神经病学 | 275篇 |
特种医学 | 258篇 |
外科学 | 799篇 |
综合类 | 219篇 |
一般理论 | 2篇 |
预防医学 | 246篇 |
眼科学 | 268篇 |
药学 | 617篇 |
2篇 | |
中国医学 | 32篇 |
肿瘤学 | 385篇 |
出版年
2023年 | 37篇 |
2022年 | 107篇 |
2021年 | 178篇 |
2020年 | 85篇 |
2019年 | 98篇 |
2018年 | 120篇 |
2017年 | 85篇 |
2016年 | 134篇 |
2015年 | 161篇 |
2014年 | 198篇 |
2013年 | 291篇 |
2012年 | 416篇 |
2011年 | 425篇 |
2010年 | 240篇 |
2009年 | 208篇 |
2008年 | 348篇 |
2007年 | 355篇 |
2006年 | 312篇 |
2005年 | 309篇 |
2004年 | 323篇 |
2003年 | 265篇 |
2002年 | 222篇 |
2001年 | 76篇 |
2000年 | 61篇 |
1999年 | 69篇 |
1998年 | 108篇 |
1997年 | 69篇 |
1996年 | 67篇 |
1995年 | 57篇 |
1994年 | 47篇 |
1993年 | 47篇 |
1992年 | 44篇 |
1991年 | 34篇 |
1990年 | 36篇 |
1989年 | 47篇 |
1988年 | 29篇 |
1987年 | 31篇 |
1986年 | 33篇 |
1985年 | 29篇 |
1984年 | 20篇 |
1983年 | 12篇 |
1982年 | 34篇 |
1981年 | 26篇 |
1980年 | 30篇 |
1979年 | 15篇 |
1978年 | 24篇 |
1977年 | 20篇 |
1976年 | 19篇 |
1975年 | 12篇 |
1974年 | 6篇 |
排序方式: 共有6048条查询结果,搜索用时 15 毫秒
991.
cAMP-dependent protein kinase activity was reduced in the cytosol fraction of spontaneously hypertensive rat (SHR) aorta compared to that of the Kyoto Wistar control rat (WKY). Two major peaks, isozymes I and II, of soluble cyclic AMP-dependent protein kinase activity could be separated by DEAE-cellulose chromatography. The distributions of isozymes I and II were 40 and 60%, respectively, in WKY compared to 26 and 74% in SHR. Isozyme I of SHR eluted at a conductance of 2–3 mmhos compared to 5–6 mmhos in WKY. In addition, activity under the peak of isozyme I of SHR was reduced by approximately 55% compared to WKY. The half-life of thermal denaturation of isozyme I at 50° was 21 min in WKY compared to 84 min in SHR. On the other hand, for isozyme II no significant differences were observed between WKY and SHR in elution pattern, total activity under the peak, or thermal denturation of enzyme activity. These data suggest that specific changes had occurred in isozyme I of SHR. 相似文献
992.
Ronnie George Hemamalini Arvind M Baskaran S Ve Ramesh Prema Raju Lingam Vijaya 《Indian journal of ophthalmology》2010,58(3):243-245
We report the prevalence and risk factors for glaucoma among aphakes and pseudophakes in 3850 subjects who participated in a population-based study in urban south India. The subjects underwent an ophthalmic examination including applanation tonometry, gonioscopy, optic disc evaluation and frequency doubling perimetry. Glaucoma was diagnosed using the International Society of Geographical and Epidemiological Ophthalmology (ISGEO) criteria. Thirty eight, 15 aphakes and 23 pseudophakes (0.99% of 3850 subjects) of the 406 persons who had undergone cataract surgery were diagnosed with glaucoma. Aphakes/pseudophakes were at higher risk of glaucoma as compared to the phakic population (Odds Ratio: 2.71, 95% CI: 1. 94, 3.38, p=0.001). On multivariate analysis, older age and higher intra ocular pressure were risk factors for glaucoma. Blindness attributable to glaucoma was detected in 20% of aphakic and 4.3% of pseudophakic eyes. Glaucoma was a significant cause of morbidity in those who had undergone cataract surgery in this urban population. 相似文献
993.
PURPOSE: Subretinal fluid (SRF) drainage and thus the potential complications of this procedure during scleral buckling can be avoided by inducing SRF absorption preoperatively. The technique described in this series is named PaCE (Pneumatic Cryo Explant). METHODS: A total of 22 eyes of 22 patients with primary bullous rhegmatogenous retinal detachment (RRD) were included in this prospective non-comparative case trial. All satisfied specific inclusion criteria similar to those used in previous pneumatic retinopexy (PR) studies. Under direct visualization, 0.3 ml C3F8 100% was injected into the vitreous cavity through the pars plana. Postoperative posturing was encouraged. Retinopexy with either cryotherapy or laser was performed, combined with scleral buckling (SB) when the SRF was absorbed. Avoidance of SRF drainage and persistent reattachment of the retina at the end of the 12-month follow-up was considered a successful outcome. A change in vision by one line (logMAR) was considered significant. RESULTS: Resolution of SRF before retinopexy and the SB procedure was achieved in 20 of 22 eyes (90.9%) and hence SRF drainage was not required. Visual improvement was achieved in 95% of cases. One eye (4.5%) lost vision due to a total RD after gas injection (further surgery was not carried out). CONCLUSION: PaCE should be considered in any suitable case of primary RRD where SRF drainage is deemed necessary. The potential complications associated with this procedure are relatively less serious and it does not compromise the viability of subsequent procedures. 相似文献
994.
We demonstrate for the first time the expression of 14.3.3sigma, an epithelial cell differentiation marker, in human corneal epithelium. 14.3.3sigma appeared at 30 kDa, pI 4-5, in 2D gels of corneal extracts. We found no significant differences in 14.3.3sigma levels between healthy corneas and corneas from keratoconus, corneal dystrophy, and corneal edema patients. 14.3.3sigma immunofluorescence was observed in the cytoplasm and nucleus of epithelial cells and colocalized with cyclin-B1. 14.3.3sigma was secreted by HCE-2 cells; HCE-2-conditioned medium induced matrix metalloproteinase-1 in cultured keratocytes. In summary, our work presents evidence of 14.3.3sigma expression in corneal epithelium and elaborates over its possible implications in corneal pathologic conditions. 相似文献
995.
Puri A Khaliq T Rajendran SM Bhatia G Chandra R Narender T 《Journal of herbal pharmacotherapy》2007,7(1):59-64
Indigofera tinctoria is a perennial shrub, which belongs to the family Papilionaceae. As a part of our drug discovery program we have investigated the antidyslipidemic activity of the alcoholic extract from Indigofera tinctoria as well as its three other components, that is, chloroform, butanol and aqueous fractions in dyslipidemic hamsters that were fed a high fat diet. The chloroform fraction showed a significant decrease in the plasma triglycerides (TG, 52%) (P < 0.001), total cholesterol (TC, 29%) (P < 0.05), glycerol (Gly, 24%) and free fatty acids (FFA, 14%). This decrease was also accompanied by an increase in high density lipoproteins (HDL) by 9% and an increased HDL-C/TC ratio of 52% at the dose of 250 mg/kg of body weight. 相似文献
996.
V Sreenivasan S Ve Ramesh Ronnie George M Baskaran 《Clinical & experimental optometry》2006,89(1):26-29
Background: The aim of this study was to assess the effect of a cylindrical corrective lens with frosted sides on Humphrey automated perimetry performed with a translucent spectacle occluder in the contralateral eye. Methods: Ten healthy volunteers with cylindrical refractive errors of more than 1.50 DC had Humphrey visual fields (30‐2) measured with the contralateral eye occluded with either a translucent spectacle occluder or an opaque patch. The order of testing with each occluder was randomised. Additionally, visual field examination with the opaque patch was performed on three volunteer subjects with deep‐set eyes to establish the clinical significance of the frosted cylindrical lens induced artefact (CLA). The back vertex distances for the correcting lenses were measured for all tests. Results: Eight out of 10 volunteers tested with the translucent occluder demonstrated CLA, which was absent when the opaque patch was used. The presence of an artefact corresponding to the axis of the cylinder was observed, when the vertex distance was more than 15 mm. Three subjects with deep‐set eyes presented with CLA, even with the use of an opaque patch. Discussion: Cylindrical lens artefacts can occur with increasing vertex distance when using a translucent spectacle occluder instead of an opaque patch. CLA is also seen in subjects with deep‐set eyes. 相似文献
997.
Murthy R Honavar SG Vemuganti GK Burman S Naik M Parathasaradhi A 《American journal of ophthalmology》2005,139(1):207-209
PURPOSE: To report the occurrence of ocular surface squamous neoplasia (OSSN) in a patient with Papillon-Lefevre syndrome. DESIGN: Interventional case report. METHODS: A 14-year-old boy presented with a progressively growing limbal lesion in the right eye for 2 months. He had associated erythematous scaly lesions on the elbows, knees, and feet with periodontosis suggestive of Papillon-Lefevre syndrome. An excision biopsy of the limbal tumor and a skin biopsy was performed. RESULTS: The limbal tumor showed features of carcinoma in situ with clear margins. The skin biopsy showed epidermal hyperplasia and hyperkeratosis with perivascular infiltrates, consistent with Papillon-Lefevre syndrome. CONCLUSIONS: Ocular surface squamous neoplasia may occur in patients with Papillon-Lefevre syndrome, an association that to the best of our knowledge has not been previously reported. 相似文献
998.
999.
1000.
Chada S Mhashilkar AM Liu Y Nishikawa T Bocangel D Zheng M Vorburger SA Pataer A Swisher SG Ramesh R Kawase K Meyn RE Hunt KK 《Cancer gene therapy》2006,13(5):490-502
Current therapies used in the treatment of breast cancer are limited by systemic toxicity, rapid drug metabolism and intrinsic and acquired drug resistance. We have previously shown that adenoviral-mediated transfer of the melanoma differentiation-associated gene-7 (mda-7) elicits growth inhibition and apoptosis in various tumor types. Here, we evaluate the effects of Ad-mda7, alone and in combination with other therapies, against a panel of nine breast tumor cell lines and their normal counterparts; we report selective Ad-mda7-mediated p53-independent growth inhibition, G2/M cell cycle arrest, and apoptosis. In vivo, Ad-mda7 induced p53-independent tumor growth inhibition (P<0.004) in multiple xenograft models. We then evaluated the combination of Ad-mda7 with agents commonly used to treat breast cancer: radiotherapy (XRT), Tamoxifen, Taxotere, Adriamycin, and Herceptin. These agents exhibit diverse modes of action, including formation of bulky adducts, inhibition of DNA replication (Adriamycin, XRT), damage to microtubules (Taxotere), nonsteroidal estrogen antagonists (Tamoxifen), or Her2/neu receptor blockade (Herceptin). Treated with conventional anticancer drugs or radiation, MDA-7-expressing cells display additive or synergistic cytotoxicity and apoptosis that correlates with decreased BCL-2 expression and BAX upregulation. In vivo, animals that received Ad-mda7 and XRT underwent significant reduction of tumor growth (P<0.002). This is the first report of the synergistic effects of Ad-mda7 combined with chemotherapy or radiotherapy on human breast carcinoma cells. 相似文献