全文获取类型
收费全文 | 2420篇 |
免费 | 103篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 26篇 |
妇产科学 | 41篇 |
基础医学 | 208篇 |
口腔科学 | 51篇 |
临床医学 | 127篇 |
内科学 | 726篇 |
皮肤病学 | 35篇 |
神经病学 | 145篇 |
特种医学 | 198篇 |
外科学 | 481篇 |
综合类 | 12篇 |
预防医学 | 39篇 |
眼科学 | 17篇 |
药学 | 85篇 |
中国医学 | 1篇 |
肿瘤学 | 348篇 |
出版年
2023年 | 21篇 |
2022年 | 30篇 |
2021年 | 60篇 |
2020年 | 29篇 |
2019年 | 30篇 |
2018年 | 44篇 |
2017年 | 41篇 |
2016年 | 45篇 |
2015年 | 51篇 |
2014年 | 86篇 |
2013年 | 87篇 |
2012年 | 163篇 |
2011年 | 148篇 |
2010年 | 96篇 |
2009年 | 73篇 |
2008年 | 105篇 |
2007年 | 114篇 |
2006年 | 121篇 |
2005年 | 136篇 |
2004年 | 111篇 |
2003年 | 87篇 |
2002年 | 83篇 |
2001年 | 60篇 |
2000年 | 55篇 |
1999年 | 74篇 |
1998年 | 35篇 |
1997年 | 31篇 |
1996年 | 27篇 |
1995年 | 18篇 |
1994年 | 25篇 |
1993年 | 23篇 |
1992年 | 61篇 |
1991年 | 44篇 |
1990年 | 45篇 |
1989年 | 34篇 |
1988年 | 35篇 |
1987年 | 36篇 |
1986年 | 28篇 |
1985年 | 24篇 |
1984年 | 11篇 |
1983年 | 19篇 |
1982年 | 7篇 |
1981年 | 11篇 |
1979年 | 8篇 |
1977年 | 7篇 |
1976年 | 6篇 |
1974年 | 10篇 |
1973年 | 7篇 |
1969年 | 6篇 |
1967年 | 5篇 |
排序方式: 共有2544条查询结果,搜索用时 0 毫秒
51.
52.
Cheng-Tse Wu Ahmed I. A. Soliman Toru Utsunomiya Takashi Ichii Hiroyuki Sugimura 《RSC advances》2019,9(55):32313
Formation of precise and high-resolution silica micropatterns on polymer substrates is of importance in surface structuring for flexible device fabrication of optics, microelectronic, and biotechnology. To achieve that, substrates modified with affinity-patterns serve as a strategy for site-selective deposition. In the present paper, vacuum ultraviolet (VUV) treatment is utilized to achieve spatially-controlled surface functionalization on a cyclo-olefin polymer (COP) substrate. An organosilane, 2,4,6,8-tetramethylcyclotetrasiloxane (TMCTS), preferentially deposits on the functionalized regions. Well-defined patterns of TMCTS are formed with a minimum feature of ∼500 nm. The secondary VUV/(O)-treatment converts TMCTS into SiOx, meanwhile etches the bare COP surface, forming patterned SiOx/COP microstructures with an average height of ∼150 nm. The resulting SiOx patterns retain a good copy of TMCTS patterns, which are also consistent with the patterns of photomask used in polymer affinity-patterning. The high quality SiOx patterns are of interests in microdevice fabrication, and the hydrophilicity contrast and adjustable heights reveal their potential application as a “stamp” for microcontact printing (μCP) techniques.Patterned surface treatment on a polymer substrate is carried out by 172 nm VUV through a photomask. TMCTS pattern formation is guided by the resulting affinity-pattern. The secondary VUV treatment converted TMCTS patterns into silica patterns. 相似文献
53.
Yoshihiko Hangai Hiroto Kamada Takao Utsunomiya Soichiro Kitahara Osamu Kuwazuru Nobuhiro Yoshikawa 《Materials》2014,7(3):2382-2394
Al foam has been used in a wide range of applications owing to its light weight, high energy absorption and high sound insulation. One of the promising processes for fabricating Al foam involves the use of a foamable precursor. In this study, ADC12 Al foams with porosities of 67%–78% were fabricated from Al alloy die castings without using a blowing agent by the friction stir processing route. The pore structure and tensile properties of the ADC12 foams were investigated and compared with those of commercially available ALPORAS. From X-ray computed tomography (X-ray CT) observations of the pore structure of ADC12 foams, it was found that they have smaller pores with a narrower distribution than those in ALPORAS. Tensile tests on the ADC12 foams indicated that as their porosity increased, the tensile strength and tensile strain decreased, with strong relation between the porosity, tensile strength, and tensile strain. ADC12 foams exhibited brittle fracture, whereas ALPORAS exhibited ductile fracture, which is due to the nature of the Al alloy used as the base material of the foams. By image-based finite element (FE) analysis using X-ray CT images corresponding to the tensile tests on ADC12 foams, it was shown that the fracture path of ADC12 foams observed in tensile tests and the regions of high stress obtained from FE analysis correspond to each other. Therefore, it is considered that the fracture behavior of ADC12 foams in relation to their pore structure distribution can be investigated by image-based FE analysis. 相似文献
54.
Sasaki K Kazama S Sunami E Tsuno NH Nozawa H Nagawa H Kitayama J 《Diseases of the colon and rectum》2012,55(1):72-78
55.
Day-by-day home blood pressure (BP) variability (BPV) was reported to be associated with increased cardiovascular risk. We aimed to test the hypothesis that the angiotensin II receptor blocker/calcium-channel blocker combination decreases day-by-day BPV more than the angiotensin II receptor blocker/diuretic combination does and investigated the mechanism underlying the former reduction. We enrolled 207 hypertensive subjects treated with olmesartan monotherapy for 12 weeks. The subjects were randomly assigned to treatment with hydrochlorothiazide (n = 104) or azelnidipine (n = 103) for 24 weeks. Home BP was taken in triplicate with a memory-equipped device in the morning and evening, respectively, for 5 consecutive days before each visit. Visits occurred at 4-week intervals. Home BPV was defined as within-individual SD of the 5-day home BP. Arterial stiffness was assessed by aortic pulse wave velocity at baseline and 24 weeks later. The reductions in home systolic BP were similar between the 2 groups, whereas the SD of home systolic BP decreased more in the azelnidipine group than in the hydrochlorothiazide group during the follow-up period (follow-up mean: 6.3 versus 7.1 mm Hg; P = 0.007). In the azelnidipine group, the change in aortic pulse wave velocity was independently associated with the change in SD of home systolic BP (regression coefficient ± SE = 0.79 ± 0.37; P = 0.036). This study demonstrated that the angiotensin II receptor blocker/calcium-channel blocker combination improved home BPV in addition to home BP reduction and that the reduction in home BPV was partly attributable to the arterial stiffness reduction by this combination. 相似文献
56.
J Ishikawa S Hoshide K Eguchi S Ishikawa K Shimada K Kario;for the Japan Morning Surge-Home Blood Pressure Study Investigators Group 《Hypertension》2012,60(4):921-928
In ambulatory blood pressure (BP) monitoring, nighttime BP has a superior ability to predict hypertensive target organ damage than awake BP. We evaluated whether nighttime BP, assessed by a home BP monitor, was associated with hypertensive target organ damage. We measured clinic BP, out-of-clinic BP including nighttime home BP, and the urinary albumin:creatinine ratio (UACR) in 854 patients who had cardiovascular risk factors. Nighttime home BP was measured at 2:00, 3:00, and 4:00 am, in addition to clinic, awake ambulatory, nighttime ambulatory, and awake home BP. Nighttime home systolic BP (SBP) was slightly higher than nighttime ambulatory SBP (difference, 2.6 mm Hg; P<0.001). Clinic (r=0.186), awake ambulatory (r=0.173), nighttime ambulatory (r=0.194), awake home (r=0.298), and nighttime home (r=0.311) SBPs were all associated with log-transformed UACR (all P<0.001). The correlation coefficient for the relationship between nighttime home SBP and log-transformed UACR was significantly greater than that for the relationship between nighttime ambulatory SBP and log-transformed UACR (P<0.001). The goodness of fit of the association between SBP and UACR was improved by adding nighttime home SBP to the other SBPs (P<0.001). Nighttime home diastolic BP also improved the goodness-of-fit of the association between diastolic BP and UACR (P=0.001). Similar findings were observed for the left ventricular mass index in the subgroup (N=594). In conclusion, nighttime home BP is slightly different from (but comparable to) nighttime ambulatory BP. The addition of nighttime home BP to other BP measures improves the association of BP with hypertensive target organ damage. 相似文献
57.
58.
59.
60.