全文获取类型
收费全文 | 923篇 |
免费 | 59篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 23篇 |
儿科学 | 13篇 |
妇产科学 | 3篇 |
基础医学 | 108篇 |
口腔科学 | 22篇 |
临床医学 | 79篇 |
内科学 | 240篇 |
皮肤病学 | 8篇 |
神经病学 | 139篇 |
特种医学 | 26篇 |
外科学 | 132篇 |
综合类 | 7篇 |
预防医学 | 47篇 |
眼科学 | 18篇 |
药学 | 75篇 |
中国医学 | 3篇 |
肿瘤学 | 42篇 |
出版年
2023年 | 11篇 |
2022年 | 32篇 |
2021年 | 57篇 |
2020年 | 25篇 |
2019年 | 39篇 |
2018年 | 51篇 |
2017年 | 36篇 |
2016年 | 36篇 |
2015年 | 36篇 |
2014年 | 36篇 |
2013年 | 52篇 |
2012年 | 61篇 |
2011年 | 75篇 |
2010年 | 44篇 |
2009年 | 47篇 |
2008年 | 49篇 |
2007年 | 66篇 |
2006年 | 49篇 |
2005年 | 46篇 |
2004年 | 37篇 |
2003年 | 28篇 |
2002年 | 27篇 |
2001年 | 8篇 |
2000年 | 4篇 |
1999年 | 6篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 7篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1982年 | 1篇 |
1927年 | 1篇 |
排序方式: 共有985条查询结果,搜索用时 15 毫秒
31.
32.
A solvent-free, low-cost, high-yield and scalable single-step ball milling process is developed to construct 2D MoS2/graphene hybrid electrodes for lithium-ion batteries. Electron microscopy investigation reveals that the obtained hybrid electrodes consist of numerous nanosheets of MoS2 and graphene which are randomly distributed. The MoS2/graphene hybrid anodes exhibit excellent cycling stability with high reversible capacities (442 mA h g−1 for MoS2/graphene (40 h); 553 mA h g−1 for MoS2/graphene (20 h); 342 mA h g−1 for MoS2/graphene (10 h)) at a high current rate of 250 mA g−1 after 100 cycles, whereas the pristine MoS2 electrode shows huge capacity fading with a retention of 37 mA h g−1 at 250 mA g−1 current after 100 cycles. The incorporation of graphene into MoS2 has an extraordinary effect on its electrochemical performance. This work emphasises the importance of the construction of the 2D MoS2/graphene hybrid structure to prevent capacity fading issues with the MoS2 anode in lithium-ion batteries.A solvent-free, low-cost, high-yield and scalable single-step ball milling process is developed to construct 2D MoS2/graphene hybrid electrodes for lithium-ion batteries. 相似文献
33.
Sacrococcygeal pilonidal sinus (SC-PSD) is an acquired condition usually seen in young adults especially males. This prospective study has been performed to determine effects of the Limberg flap rotation surgery for sacrococcygeal pilonidal sinus, its feasibility to the patients, their compliance, and outcomes such as wound infection, postoperative pain relief, recurrence rates, and return to work. A total of 30 patients were operated by the same two surgeons from January 2009 to June 2011, including both primary and recurrent diseases, and patients with previous incision and drainage done for the pilonidal abscess. All patients successfully underwent surgery, with very minimal postoperative pain, stayed in hospital for average 5 days, returned to work after 3 weeks, with 3 patients having flap edema, 2 having flap necrosis, and no recurrences so far. Patients with flap edema and flap necrosis took 2–3 weeks to heal with regular dressing and antibiotic usage. Limberg flap for sacrococcygeal pilonidal sinus was found very useful and sound in terms of postoperative pain, infection rates, and early return to work with almost nil recurrences. 相似文献
34.
35.
Satyaveni Malasala Jitendra Gour Md. Naiyaz Ahmad Srikanth Gatadi Manjulika Shukla Grace Kaul Arunava Dasgupta Y. V. Madhavi Sidharth Chopra Srinivas Nanduri 《RSC advances》2020,10(71):43533
A facile method was developed for the synthesis of quinazolinone derivatives in a one-pot condensation reaction via in situ amine generation using ammonia as the amine source and with the formation of four new C–N bonds in good to excellent yields. With the optimised method, we synthesized a library of piperazine linked quinazoline derivatives and the synthesized compounds were evaluated for their inhibitory activity against Mycobacterium tuberculosis. The compounds 8b, 8e, 8f, 8m, 8n and 8v showed potent anti-mycobacterial activity with MIC values of 2–16 μg mL−1. All the synthesized compounds follow Lipinski''s rules for drug likeness.A facile method was developed for the synthesis of quinazolinone derivatives in a one-pot condensation reaction via in situ amine generation using ammonia as the amine source and with the formation of four new C–N bonds in good to excellent yields. 相似文献
36.
P.?Srikanth R.?F.?Chun M.?Hewison J.?S.?Adams R.?Bouillon D.?Vanderschueren N.?Lane P.?M.?Cawthon T.?Dam E.?Barrett-Connor L.?B.?Daniels J.?M.?Shikany M.?L.?Stefanick J.?A.?Cauley E.?S.?Orwoll C.?M.?Nielson for the Osteoporotic Fractures in Men Study Research Group 《Osteoporosis international》2016,27(7):2291-2300
Summary
Vitamin D is hypothesized to suppress inflammation. We tested total and free vitamin D metabolites and their association with inflammatory markers. Interleukin-6 levels were lower with higher 25-hydroxyvitamin D. 1,25-dihydroxyvitamin D and free 25OHD associations mirrored those of 25OHD. However, associations for the two metabolites diverged for tumor necrosis factor alpha (TNF-α) soluble receptors.Introduction
Vitamin D is hypothesized to suppress inflammation, and circulating 25-hydroxyvitamin D (25OHD) and inflammatory markers are inversely correlated. However, total serum 25OHD may not be the best indicator of biologically active vitamin D.Methods
We tested serum total 25OHD, total 1,25(OH)2D, vitamin D binding protein (DBP), and estimated free 25OHD and free 1,25(OH)2D associations with inflammatory markers serum interleukin-6 (IL-6), TNF-α and their soluble receptors, interleukin-10 (IL-10), and C-reactive protein (CRP) as continuous outcomes and the presence of ≥2 inflammatory markers in the highest quartile as a dichotomous outcome, in a random subcohort of 679 men in the Osteoporotic Fractures in Men (MrOS) study.Results
IL-6 was lower in men with higher 25OHD (?0.23 μg/mL per standard deviation (SD) increase in 25OHD, 95 % confidence intervals (CI) ?0.07 to ?0.38 μg/mL) and with higher 1,25(OH)2D (?0.20 μg/mL, 95 % CI ?0.0004 to ?0.39 μg/mL); free D associations were slightly stronger. 25OHD and DBP, but not 1,25(OH)2D, were independently associated with IL-6. TNF-α soluble receptors were inversely associated with 1,25(OH)2D but positively associated with 25OHD, and each had independent effects. The strongest association with ≥2 inflammatory markers in the highest quartile was for free 1,25(OH)2D (odds ratios (OR) 0.70, 95 % CI 0.54 to 0.89 per SD increase in free 1,25(OH)2D).Conclusions
Associations of 1,25(OH)2D and free 25OHD with IL-6 mirrored those of 25OHD, suggesting that 1,25(OH)2D and free D do not improve upon 25OHD in population-based IL-6 studies. However, associations for the two metabolites diverged for TNF-α soluble receptor, warranting examination of both metabolites in studies of TNF-α and its antagonists.37.
In response to DNA damage, cell cycle arrest, apoptosis, and DNA repair are mediated by a TP53 pathway that induces p21(WAF1/Cip1). The chemotherapeutic drug cis-diamminedichloroplatinum-II (cisplatin) damages cellular DNA by forming cis-diammineplatinum-N(7)-d[GpG] and cis-diammine-platinum-N(7)-d[ApG] adducts. To investigate the role of p21, skin keratinocytes from p21(WAF1/Cip1) wild-type (+/+), heterozygous (+/-), and null (-/-) mice, cultured in calcium levels designed to maintain a proliferating state, were exposed to 5 microM cisplatin continuously for 0, 8, 24, 48 and 72 h. At all time points the (+/-) cells had the fewest Pt-DNA adducts, and at 24 h mean Pt-DNA adduct levels were 541, 153 and 779 fmol adduct/mug DNA for p21(WAF1/Cip1) (+/+), (+/-) and (-/-) cells, respectively [P < 0.05 for (+/+) versus (+/-) and (-/-) versus (+/-)]. In order to understand underlying events, we examined p21(WAF1/Cip1) messenger RNA (mRNA), cell cycle arrest, and apoptosis in these cells. At 48 h of cisplatin exposure p21(WAF1/Cip1) mRNA expression was 2-fold higher in the (+/+) cells, compared to the (+/-) cells. At 24 h, the % of cells in S-phase in cisplatin-exposed cultures, compared to unexposed cultures, was decreased by 51, 40 and 11% in p21(WAF1/Cip1) (+/+), (+/-) and (-/-) cells, respectively (P = 0.04, ANOVA). At 24, 48 and 72 h the % of cisplatin-exposed (+/+) cells in apoptosis was 9.4-10.5%, while the cisplatin-exposed (+/-) and (-/-) cells had 1.2-3.7% of cells in apoptosis. The data support the interpretation that DNA replication arrest and apoptosis do not completely explain the low levels of Pt-DNA adducts in the (+/-) cells, and suggest that p21(WAF1/Cip1) controls activity resulting in either low Pt-DNA adduct formation or enhanced Pt-DNA adduct removal. 相似文献
38.
39.
40.
Srikanth Yandrapalli MD Howard A Cooper MD Ramin Malekan MD 《Journal of cardiac surgery》2020,35(9):2361-2363
The coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is overwhelming healthcare resources and infrastructure worldwide. Earlier reports have demonstrated complicated postoperative courses and high fatality rates in patients undergoing emergent cardiothoracic surgery who were diagnosed postoperatively with COVID-19. These reports raise the possibility that active COVID-19 might precipitate a catastrophic pathophysiological response to infection in the postoperative period and lead to unfavorable surgical outcomes. Hence, it is imperative to screen patients with SARS-CoV-2 infection before surgery and to carefully monitor them in the postoperative period to identify any signs of active COVID-19. In this report, we present the successful outcome of coronary artery bypass grafting (CABG) operation in a patient with asymptomatic SARS-CoV-2 infection presenting with an acute coronary syndrome and requiring urgent surgical intervention. We employed a thorough strategy to identify subclinical COVID-19 disease, and after confirming the absence of active disease, proceeded with the CABG operation. The patient outcome was successful with the absence of any overt COVID-19 manifestations in the postoperative period. 相似文献