全文获取类型
收费全文 | 4077篇 |
免费 | 109篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 63篇 |
儿科学 | 50篇 |
妇产科学 | 50篇 |
基础医学 | 522篇 |
口腔科学 | 123篇 |
临床医学 | 220篇 |
内科学 | 991篇 |
皮肤病学 | 32篇 |
神经病学 | 211篇 |
特种医学 | 141篇 |
外科学 | 574篇 |
综合类 | 14篇 |
预防医学 | 101篇 |
眼科学 | 164篇 |
药学 | 480篇 |
中国医学 | 13篇 |
肿瘤学 | 450篇 |
出版年
2023年 | 18篇 |
2022年 | 33篇 |
2021年 | 90篇 |
2020年 | 32篇 |
2019年 | 50篇 |
2018年 | 64篇 |
2017年 | 34篇 |
2016年 | 61篇 |
2015年 | 60篇 |
2014年 | 107篇 |
2013年 | 103篇 |
2012年 | 153篇 |
2011年 | 217篇 |
2010年 | 123篇 |
2009年 | 129篇 |
2008年 | 210篇 |
2007年 | 229篇 |
2006年 | 282篇 |
2005年 | 280篇 |
2004年 | 282篇 |
2003年 | 246篇 |
2002年 | 294篇 |
2001年 | 100篇 |
2000年 | 84篇 |
1999年 | 84篇 |
1998年 | 73篇 |
1997年 | 62篇 |
1996年 | 63篇 |
1995年 | 37篇 |
1994年 | 37篇 |
1993年 | 36篇 |
1992年 | 56篇 |
1991年 | 63篇 |
1990年 | 39篇 |
1989年 | 44篇 |
1988年 | 39篇 |
1987年 | 45篇 |
1986年 | 37篇 |
1985年 | 39篇 |
1984年 | 29篇 |
1983年 | 21篇 |
1982年 | 7篇 |
1981年 | 20篇 |
1980年 | 8篇 |
1979年 | 16篇 |
1978年 | 9篇 |
1977年 | 14篇 |
1976年 | 11篇 |
1975年 | 6篇 |
1972年 | 4篇 |
排序方式: 共有4199条查询结果,搜索用时 15 毫秒
71.
Shingo Machida Reo Kato Kaishi Hasegawa Takahiro Gotoh Ken-ichi Katsumata Atsuo Yasumori 《Materials》2022,15(15)
Photoreduction of Cu2+ ions to Cu metal by titanium(IV) oxide (TiO2) was conducted in the presence of a silica–surfactant hybrid under sulfuric acid conditions. After irradiation, a dark-red color, reflections due to Cu metal in the X-ray diffraction pattern, and peaks due to Cu 2p1/2 and 2p3/2 in the X-ray photoelectron spectrum indicated the precipitation of Cu metal in the product. In addition, an increase in the Brunauer–Emmett–Teller specific surface area from 36 and 45 m2/g for the silica–surfactant and TiO2, respectively, to 591 m2/g for the product, and a decrease in the intensity of the C-H stretching band in the Fourier–transform infra-red spectra implied the removal of surfactant during the reaction. These characteristics were never observed when TiO2 was used solely. Therefore, this study indicated that the photoreduction of Cu2+ ions to Cu metal by TiO2 was facilitated under the sulfuric acid medium, where the surfactants extracted from silica–surfactant hybrids by protons in the acidic condition were successfully photo-oxidized by TiO2. Thus, this study presents a new application of the conversion of a silica–surfactant hybrid into mesoporous silicas. 相似文献
72.
73.
Mori M Imagawa T Katakura S Miyamae T Okuyama K Ito S Nakamura T Kimura H Yokota S 《Modern rheumatology / the Japan Rheumatism Association》2004,14(1):43-47
Kawasaki disease (KD) causes coronary artery lesions (CALs) in 500 Japanese children each year. Intravenous gamma-globulin (IVGG) decreases the incidence of these lesions from 25% to 8% of the total KD cases. We examined whether plasma exchange is a safe and effective prophylaxis against CALs in children with KD intractable to IVGG therapy. Eighty-nine children with KD at high risk of CALs were selected on the basis of increases in fractional changes in inflammatory markers such as white blood cell count, neutrophil count, and C-reactive protein between the baseline and 1–2 days after IVGG treatment. Of 105 children who received a second course of IVGG therapy because the initial course was ineffective, plasma exchange (PE) was performed in 46 children who had not responded to the second IVGG treatment. The outcome was compared with the results when a third course of IVGG therapy was given to the other 59 children. No complications occurred with the plasma exchange therapy. CALs developed in only 8 of the 46 children (17.3%) who underwent plasma exchange, but they occurred in 24 of the 59 (40.7%) who had received a third course of IVGG therapy (P 0.0012). We concluded that PE was a safe, effective prophylactic measure against CALs in children with KD intractable to IVGG therapy. PE should be performed at an early stage, as soon as fractional increases in inflammatory markers are found after IVGG therapy. 相似文献
74.
Yagi S Aihara K Ikeda Y Sumitomo Y Yoshida S Ise T Iwase T Ishikawa K Azuma H Akaike M Matsumoto T 《Circulation research》2008,102(1):68-76
Angiotensin II (Ang II) plays a pivotal role in cardiovascular remodeling leading to hypertension, myocardial infarction, and stroke. Pitavastatin, an HMG-CoA reductase inihibitor, is known to have pleiotropic actions against the development of cardiovascular remodeling. The objectives of this study were to clarify the beneficial effects as well as the mechanism of action of pitavastatin against Ang II-induced organ damage. C57BL6/J mice at 10 weeks of age were infused with Ang II for 2 weeks and were simultaneously administered pitavastatin or a vehicle. Pitavastatin treatment improved Ang II-induced left ventricular hypertrophy and diastolic dysfunction and attenuated enhancement of cardiac fibrosis, cardiomyocyte hypertrophy, coronary perivascular fibrosis, and medial thickening. Ang II-induced oxidative stress, cardiac TGFbeta-1 expression, and Smad 2/3 phosphorylation were all attenuated by pitavastatin treatment. Pitavastatin also reduced Ang II-induced cardiac remodeling and diastolic dysfunction in eNOS-/- mice as in wild-type mice. In eNOS-/- mice, the Ang II-induced cardiac oxidative stress and TGF-beta-Smad 2/3 signaling pathway were enhanced, and pitavastatin treatment attenuated the enhanced oxidative stress and the signaling pathway. Moreover, pitavastatin treatment reduced the high mortality rate and improved renal insufficiency in Ang II-treated eNOS-/- mice, with suppression of glomerular oxidative stress and TGF-beta-Smad 2/3 signaling pathway. In conclusion, pitavastatin exerts eNOS-independent protective actions against Ang II-induced cardiovascular remodeling and renal insufficiency through inhibition of the TGF-beta-Smad 2/3 signaling pathway by suppression of oxidative stress. 相似文献
75.
Teiichi Yamane Taro Date Yasuko Kanzaki Keiichi Inada Seiichiro Matsuo Kenri Shibayama Satoru Miyanaga Hidekazu Miyazaki Ken-ichi Sugimoto Seibu Mochizuki 《Circulation journal》2007,71(5):753-760
BACKGROUND: The limited efficacy and complications of segmental ostial pulmonary vein isolation (PVI) for treating atrial fibrillation (AF) have been discussed so, in the present study the feasibility and efficiency of performing segmental pulmonary vein (PV) antrum isolation to treat AF were assessed. METHODS AND RESULTS: A total of 187 patients with drug-refractory AF (paroxysmal 120, persistent 67) underwent segmental PVI guided by circumferential 20-electrode catheters (Lasso). Radiofrequency (RF) current was delivered either at the ostium using a regular Lasso (15-20 mm in diameter, 70 patients: Group 1) or at the antrum using a larger Lasso (25-30 mm in diameter, 117 patients: Group 2). A significantly wider region had to be ablated, with a longer RF application time, to isolate all 4 PVs in Group 2 patients than in Group 1 patients. Although the rate of recurrence of AF after the initial session was equal in both groups, a significantly greater number of patients were free from AF after a mean of 1.4 procedures in Group 2 than in Group 1 (93% vs 76% for paroxysmal AF, 78% vs 48% for persistent AF). CONCLUSIONS: Segmental antral PVI using large-sized Lasso catheters was found to be more effective and safer than ostial PVI for the treatment of AF. 相似文献
76.
Different Adhesive Characteristics and VLA-4 Expression of CD34+ Progenitors in G0/G1 Versus S+G2/M Phases of the Cell Cycle 总被引:2,自引:3,他引:2
77.
78.
N Emoto T Tsushima K Shizume T Tanaka M Saji Y Ohba K Wakai M Arai E Ohmura 《Acta endocrinologica》1987,114(2):283-291
Nb2 cell is a rat lymphoma cell line that responds to lactogens such as prolactin and human growth hormone (hGH) with an increased rate of proliferation. We explored the relationship between the biochemical events induced by hGH and its derivatives and their receptor binding activities. hGH stimulated RNA, DNA and protein synthesis of Nb2 cells as a function of time. Stimulation of RNA and protein was maximal at 2-3 h and 12 h, respectively, after the addition of hGH. DNA synthesis, measured by the rate of [3H]thymidine incorporation, reached a maximum after 18-h incubation with hGH. Stimulation of DNA synthesis was elicited by hGH in a dose-dependent manner between 0.45 and 45 pmol/l. The activity of the 20 K hGH variant in stimulating DNA synthesis was approx 30% of that of hGH. In contrast, S1-hGH, which lacks a sequence of ten amino acids (140-149) of hGH, showed a 3.2-fold greater activity than hGH. F1 (amino-terminal sequence 1-134 of hGH) was only 0.06% as active as hGH, and the activity of F2 (C-terminal 42 amino acid residue of hGH) was less than 0.01%. Both fragment 1-15 and 32-46 were without effect. The relative potencies of these hGH derivatives in stimulating DNA synthesis were similar to their relative abilities to inhibit [125I]hGH binding to lactogenic receptors on Nb2 cell. Nb2 cells provide a suitable model to study the relationship between receptor binding and the biochemical events induced by lactogens. 相似文献
79.
Microvascular resistance in response to iodinated contrast media in normal and functionally impaired kidneys 下载免费PDF全文
Osamu Kurihara Masamichi Takano Saori Uchiyama Isamu Fukuizumi Tetsuro Shimura Masato Matsushita Hidenori Komiyama Toru Inami Daisuke Murakami Ryo Munakata Takayoshi Ohba Noritake Hata Yoshihiko Seino Wataru Shimizu 《Clinical and experimental pharmacology & physiology》2015,42(12):1245-1250
Contrast‐induced nephropathy (CIN) is considered to result from intrarenal vasoconstriction, and occurs more frequently in impaired than in normal kidneys. It was hypothesized that iodinated contrast media would markedly change renal blood flow and vascular resistance in functionally impaired kidneys. Thirty‐six patients were enrolled (32 men; mean age, 75.3 ± 7.6 years) undergoing diagnostic coronary angiography and were divided into two groups based on the presence of chronic kidney disease (CKD), defined as an estimated glomerular filtration rate (eGFR) of < 60 mL/min per 1.73 m2 (CKD and non‐CKD groups, n = 18 in both). Average peak velocity (APV) and renal artery resistance index (RI) were measured by Doppler flow wire before and after administration of the iodinated contrast media. The APV and the RI were positively and inversely correlated with the eGFR at baseline, respectively (APV, R = 0.545, P = 0.001; RI, R = ?0.627, P < 0.001). Mean RI was significantly higher (P = 0.015) and APV was significantly lower (P = 0.026) in the CKD than in the non‐CKD group. Both APV (P < 0.001) and RI (P = 0.002) were significantly changed following contrast media administration in the non‐CKD group, but not in the CKD group (APV, P = 0.258; RI, P = 0.707). Although renal arterial resistance was higher in patients with CKD, it was not affected by contrast media administration, suggesting that patients with CKD could have an attenuated response to contrast media. 相似文献
80.