全文获取类型
收费全文 | 5393篇 |
免费 | 421篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 22篇 |
儿科学 | 193篇 |
妇产科学 | 91篇 |
基础医学 | 791篇 |
口腔科学 | 53篇 |
临床医学 | 613篇 |
内科学 | 1249篇 |
皮肤病学 | 97篇 |
神经病学 | 530篇 |
特种医学 | 125篇 |
外科学 | 638篇 |
综合类 | 54篇 |
一般理论 | 1篇 |
预防医学 | 565篇 |
眼科学 | 81篇 |
药学 | 428篇 |
中国医学 | 16篇 |
肿瘤学 | 288篇 |
出版年
2024年 | 12篇 |
2023年 | 82篇 |
2022年 | 114篇 |
2021年 | 230篇 |
2020年 | 146篇 |
2019年 | 205篇 |
2018年 | 206篇 |
2017年 | 154篇 |
2016年 | 178篇 |
2015年 | 194篇 |
2014年 | 219篇 |
2013年 | 285篇 |
2012年 | 423篇 |
2011年 | 453篇 |
2010年 | 237篇 |
2009年 | 196篇 |
2008年 | 366篇 |
2007年 | 321篇 |
2006年 | 369篇 |
2005年 | 327篇 |
2004年 | 299篇 |
2003年 | 271篇 |
2002年 | 190篇 |
2001年 | 33篇 |
2000年 | 22篇 |
1999年 | 40篇 |
1998年 | 40篇 |
1997年 | 31篇 |
1996年 | 22篇 |
1995年 | 31篇 |
1994年 | 16篇 |
1993年 | 13篇 |
1992年 | 13篇 |
1991年 | 12篇 |
1990年 | 12篇 |
1989年 | 17篇 |
1988年 | 4篇 |
1987年 | 8篇 |
1986年 | 6篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1967年 | 2篇 |
1924年 | 1篇 |
1906年 | 1篇 |
排序方式: 共有5835条查询结果,搜索用时 15 毫秒
991.
Vlak T Kaštelan D Lozo P Aljinović J Gradišer M Mijić S Nikolić T Miškić B Car D Tajšić G Dušek T Jajić Z Grubišić F Poljičanin T Bakula M Džubur F Strižak-Ujević M Kadojić M Radman M Vugrinec M Kuster Z Pekez M Radović E Labar L Crnčević-Orlić Z Koršić M 《Clinical rheumatology》2011,30(12):1549-1554
A prospective, open-labelled, multicentre 6-month study was designed to assess three categories that have high impact on Health-Related Quality of Life (HR-QoL). These categories were: satisfaction, preference and drug tolerability in postmenopausal patients with osteoporosis in Croatia, at first treated with weekly oral bisphosphonates, followed by monthly oral ibandronate. Three hundred eighty-five postmenopausal women who were treated with one of the weekly bisphosphonates for at least 6?months were included into the study and after they had signed written informed consent, the therapy was changed to monthly ibandronate. Satisfaction with the treatment was assessed with the Osteoporosis Patient Satisfaction Questionnaire (OPSAT-Q). Patients completed OPSAT-Q at the baseline visit before the change of therapy (visit 1) and 6?months after the change of therapy (visit 2). Following 6?months ibandronate therapy, the values in all four domains of the OPSAT-Q (convenience, confidence with daily activities, overall satisfaction, side effects) as well as in the Composite Satisfaction Score were higher in visit 2 (p?0.001). Values in subjects enrolled into the patient assistance programme did not differ significantly from the values in subjects that were not (p?=?0.399) except for the domain convenience (p?=?0.026). This study demonstrates significantly higher satisfaction in patients who switched from the weekly bisphosphonate therapy regimen to monthly ibandronate in all observed aspects of treatment. Patients expressed preference for monthly bisphosphonate (ibandronate) in comparison with weekly bisphosphonates and found it to be a more convenient method of treatment. At the time of study, however, it was not known that the anti-fracture effect of ibandronate was smaller for hip fractures than with other bisphosphonates. 相似文献
992.
993.
994.
Jimenez T McDermott JP Sánchez G Blanco G 《Proceedings of the National Academy of Sciences of the United States of America》2011,108(2):644-649
Regulation of ion balance in spermatozoa has been shown to be essential for sperm motility and fertility. Control of intracellular ion levels requires the function of distinct ion-transport mechanisms at the cell plasma membrane. Active Na(+) and K(+) exchange in sperm is under the control of the Na,K-ATPase. Two molecular variants of the catalytic subunit of the Na,K-ATPase, α1 and α4, coexist in sperm. These isoforms exhibit different biochemical properties; however, their function in sperm fertility is unknown. In this work, we show that Na,K-ATPase α4 is essential for sperm fertility. Knockout male mice lacking α4 are completely sterile and spermatozoa from these mice are unable of fertilizing eggs in vitro. Furthermore, α4 deletion results in severe reduction in sperm motility and hyperactivation typical of sperm capacitation. In addition, absence of α4 causes a characteristic bend in the sperm flagellum, indicative of abnormal sperm ion regulation. Accordingly, α4-null sperm present increased intracellular Na(+) and cell plasma membrane depolarization. These results are unique in demonstrating the absolute requirement of α4 for sperm fertility. Moreover, the inability of α1 to compensate for α4 suggests that α4 is the Na,K-ATPase-α isoform directly involved in sperm fertility. Our findings show α4 as an attractive target for male contraception and open the possibility for the potential use of this Na,K-ATPase isoform as a biomarker for male fertility. 相似文献
995.
996.
Background
Hydroxymethylglutaryl–coenzyme A reductase inhibitors (statins) have been shown to reduce sympathetic nervous system (SNS) activation in experimental heart failure (HF). However, this potential mechanism of action of statins in HF has not been well studied in humans.Methods and Results
Twenty-six patients with nonischemic systolic HF (left ventricular ejection fraction [LVEF] ≤35%) were randomized to atorvastatin (10 mg) or placebo for 3 months. Pre- and posttreatment testing included echocardiography, laboratory assays, quality of life (QOL) questionnaires, and peroneal nerve muscle sympathetic nerve activity (MSNA) via microneurography. Eighteen subjects had technically adequate MSNA tracings before and after treatment. The cohort was 65% male, 81% New York Heart Association functional class II, LVEF 26 ± 6%, and low-density lipoprotein cholesterol (LDL-C) 108 ± 26 mg/dL. Baseline MSNA was 41 ± 2 bursts/min. LDL-C significantly decreased in the atorvastatin (−36.8%) versus the placebo (−0.1%) group (P < .0001). However, there was no significant change in MSNA (−16.2% vs −2.5%), LVEF, B-type natriuretic peptide, or QOL score in the atorvastatin compared with the placebo group.Conclusions
Short-term statin therapy in patients with nonischemic HF does not result in a significant decrease in SNS activation as measured by MSNA. These findings are consistent with the neutral outcomes of large clinical trials of statins in HF. 相似文献997.
Sanders JL Iannaccone A Boudreau RM Conley YP Opresko PL Hsueh WC Cummings SR Cawthon RM Harris TB Nalls MA Kritchevsky SB Newman AB;Health ABC Study 《The journals of gerontology. Series A, Biological sciences and medical sciences》2011,66(6):639-645
Lens transparency, or the magnitude of cataract severity, is a potential in vivo marker of aging distinguishable from diagnosed cataract. To explore lens transparency as a marker of aging, we determined its association with leukocyte telomere length (LTL) measured with quantitative polymerase chain reaction. Cataract severity was directly measured in 259 participants, and prevalent cataract and incident cataract surgery were ascertained in 2,750 participants of the Health, Aging, and Body Composition Study. LTL was unassociated with clinical cataract outcomes. Six of 259 had successfully aged lenses and a mean LTL of 5,700 bp, whereas 253/259 with poorly aged lenses had a mean LTL of 4,770 bp. Participants with a 1,000 bp greater mean LTL had nearly half the odds of any cataract (odds ratio = 0.47, 95% confidence interval 0.22-1.02) after adjustment. Lens transparency might be associated with longer LTL in community-dwelling older adults and should be investigated further as a possible biomarker of aging. 相似文献
998.
999.
1000.
Jana Rado?inská Vladimír Knezl Tamara Benová L’ubomír Urban Narcis Tribulová Ján Slezák 《Experimental & Clinical Cardiology》2011,16(4):116-120
Ventricular fibrillation (VF) is a life-threatening arrhythmia, whose occurrence precedes the development of myocardial arrhythmogenic substrate resulting from either chronic or acute pathophysiological conditions. The authors’ previous and current studies suggest that downregulated and/or heterogeneously distributed cell-to-cell coupling protein – connexin-43 (Cx43) – facilitates the development of malignant arrhythmias. It was hypothesized that VF itself deteriorates Cx43, and may hamper cardioversion into sinus rhythm. The purpose of the present study was to examine whether myocardial expression and the phosphorylated status of Cx43 is altered due to VF and during sinus rhythm restoration. Experiments were performed using 10-month-old male and female Wistar rats. Isolated Langendorff-mode-perfused rat hearts were subjected to the following events: basal condition, electrically induced VF lasting 2 min, electrically induced VF lasting 10 min, and sustained VF followed by spontaneous sinus rhythm restoration due to transient stop perfusion. The hearts were snap frozen at each event; ventricular tissue was sent for Cx43 immunoblotting using rabbit antiCx43 polyclonal antibody to detect phosphorylated (P-Cx43) as well as unphosphorylated (noP-Cx43) forms of Cx43, and mouse antiCx43 monoclonal antibody to detect noP-Cx43 only. Compared with basal conditions, total Cx43 expression did not change during experiments in either male or female rat hearts. However, P-Cx43 and the ratio of P-Cx43 to total Cx43 decreased significantly due to VF lasting 2 min and 10 min in male rat hearts only. In parallel, there was a significant increase in noP-Cx43 due to VF lasting 2 min and 10 min in male rat hearts only. Surprisingly, an enhancement of noP-Cx43 linked with suppression of P-Cx43 was detected during stop perfusion-induced termination of VF lasting 2 min, followed by sinus rhythm restoration in both male and female rat hearts. Sinus rhythm was not restored after 10 min of VF, which caused pronounced Cx43 dephosphorylation. In conclusion, there is a downregulation of Cx43 due to sustaining of VF, and it occurs earlier in male rat hearts compared with female rat hearts. It appears that transient no-flow-related inhibition of cell-to-cell coupling, as indicated by an increase in nonP-Cx43, can terminate VF followed by sinus rhythm restoration depending on the degree of previous Cx43 downregulation. 相似文献