全文获取类型
收费全文 | 6828篇 |
免费 | 288篇 |
国内免费 | 38篇 |
专业分类
耳鼻咽喉 | 150篇 |
儿科学 | 78篇 |
妇产科学 | 48篇 |
基础医学 | 870篇 |
口腔科学 | 141篇 |
临床医学 | 432篇 |
内科学 | 1625篇 |
皮肤病学 | 110篇 |
神经病学 | 356篇 |
特种医学 | 238篇 |
外科学 | 1370篇 |
综合类 | 41篇 |
预防医学 | 205篇 |
眼科学 | 42篇 |
药学 | 558篇 |
中国医学 | 4篇 |
肿瘤学 | 886篇 |
出版年
2023年 | 44篇 |
2022年 | 100篇 |
2021年 | 140篇 |
2020年 | 80篇 |
2019年 | 88篇 |
2018年 | 135篇 |
2017年 | 99篇 |
2016年 | 108篇 |
2015年 | 121篇 |
2014年 | 148篇 |
2013年 | 164篇 |
2012年 | 321篇 |
2011年 | 375篇 |
2010年 | 181篇 |
2009年 | 170篇 |
2008年 | 293篇 |
2007年 | 354篇 |
2006年 | 322篇 |
2005年 | 342篇 |
2004年 | 340篇 |
2003年 | 313篇 |
2002年 | 298篇 |
2001年 | 184篇 |
2000年 | 203篇 |
1999年 | 201篇 |
1998年 | 72篇 |
1997年 | 72篇 |
1996年 | 66篇 |
1995年 | 65篇 |
1994年 | 64篇 |
1993年 | 50篇 |
1992年 | 124篇 |
1991年 | 128篇 |
1990年 | 133篇 |
1989年 | 125篇 |
1988年 | 129篇 |
1987年 | 132篇 |
1986年 | 126篇 |
1985年 | 104篇 |
1984年 | 71篇 |
1983年 | 75篇 |
1979年 | 44篇 |
1978年 | 30篇 |
1977年 | 36篇 |
1973年 | 38篇 |
1972年 | 33篇 |
1971年 | 37篇 |
1970年 | 29篇 |
1969年 | 29篇 |
1968年 | 34篇 |
排序方式: 共有7154条查询结果,搜索用时 15 毫秒
121.
Hiroki Ueno Narumi Ohno Takafumi Abe Kazuki Kimoto Chika Matsuoka Mayumi Giga Hiroyuki Naito Tomoyuki Kono Miyuki Takasu Naoya Kidani Rie Yamasaki Koichi Ichimura Eiichi Nomura 《Internal medicine (Tokyo, Japan)》2022,61(24):3733
Central nervous system methotrexate-associated lymphoproliferative disorder (CNS-MTX-LPD) is rare, but its spontaneous regression has been observed in some patients after withdrawal of agents. We herein report three cases of primary CNS-MTX-LPD that received oral MTX for rheumatoid arthritis. Epstein-Barr virus and oligoclonal bands (OCBs) were positive, while proton magnetic resonance spectroscopy (1H-MRS) showed an elevated lipid peak and slightly elevated choline/N-acetylaspartate ratio in common. After MTX withdrawal, brain lesions showed spontaneous regression in all cases. Our patient''s 1H-MRS findings and OCBs may reflect a non-monoclonal lymphoproliferative histology as benign-type lesions in CNS-MTX-LPD. 相似文献
122.
123.
Takehiro Fujita Masami Shuta Mika Mano Shinnosuke Matsumoto Atsushi Nagasawa Akihiro Yamada Masanobu Naito 《Materials》2023,16(1)
In recent years, there has been considerable research into functional materials inspired by living things. Much attention has been paid to the development of adhesive materials that mimic the adhesive proteins secreted by a mussel’s foot. These mussel-inspired materials have superior adhesiveness to various adherents owing to the non-covalent interactions of their polyphenolic moieties, e.g., hydrogen bonding, electrostatic interactions, and even hydrophobic interactions. Various factors significantly affect the adhesiveness of mussel-inspired polymers, such as the molecular weight, cross-linking density, and composition ratio of the components, as well as the chemical structure of the polyphenolic adhesive moieties, such as l-3,4-dihydroxyphenylalanine (l-Dopa). However, the contributions of the position and distribution of the adhesive moiety in mussel-inspired polymers are often underestimated. In the present study, we prepared a series of mussel-inspired alkyl methacrylate copolymers by controlling the position and distribution of the adhesive moiety, which are known as “forced gradient copolymers”. We used a newly designed gallic-acid-bearing methacrylate (GMA) as the polyphenolic adhesive moiety and copolymerized it with 2-ethylhexyl methacrylate (EHMA). The resulting forced gradient adhesive copolymer of GMA and EHMA (poly(GMA-co-EHMA), Poly1) was subjected to adhesion and dispersion tests with an aluminum substrate and a BaTiO3 nanoparticle in organic solvents, respectively. In particular, this study aims to clarify how the monomer position and distribution of the adhesive moiety in the mussel-inspired polymer affect its adhesion and dispersion behavior on a flat metal oxide surface and spherical inorganic oxide surfaces of several tens of nanometers in diameter, respectively. Here, forced gradient copolymer Poly1 consisted of a homopolymer moiety of EHMA (Poly3) and a random copolymer moiety of EHMA and GMA (Poly4). The composition ratio of GMA and the molecular weight were kept constant among the Poly1 series. Simultaneous control of the molecular lengths of Poly3 and Poly4 allowed us to discuss the effects on the distribution of GMA in Poly1. Poly1 exhibited apparent distribution dependency with regard to the adhesiveness and the dispersibility of BaTiO3. Poly1 showed the highest adhesion strength when the composition ratio of GMA was approximately 9 mol% in the portion of the Poly4 segment. In contrast, the block copolymer consisting of the Poly3 segment and Poly4 segment with only adhesive moiety 1 showed the lowest viscosity for dispersion of BaTiO3 nanoparticles. These results indicate that copolymers with mussel-inspired adhesive motifs require the proper design of the monomer position and distribution in Poly1 according to the shape and characteristics of the adherend to maximize their functionality. This research will facilitate the rational design of bio-inspired adhesive materials derived from plants that outperform natural materials, and it will eventually contribute to a sustainable circular economy. 相似文献
124.
Haruhisa Kato Makiko Naito Tomoko Saito Takuto Hideyama Yasuhiro Suzuki Takashi Kimura Shin Kwak Hitoshi Aizawa 《JOURNAL OF CLINICAL NEUROLOGY》2022,18(4):463
Background and PurposeAmyotrophic lateral sclerosis (ALS) is a fatal motor neuron disease. Selective deficiency of edited adenosine deaminase acting on RNA 2 (ADAR2), a key molecule in the acquisition of Ca2+ resistance in motor neurons, has been reported in sporadic ALS (sALS) spinal motor neurons. Since ADAR2 activity is positively regulated by prolyl isomerase Protein never in mitosis gene A interacting-1 (Pin1), a known phosphorylation-dependent peptidyl-prolyl cis/trans isomerase, we investigated Pin1 expression in spinal motor neurons in sALS.MethodsSpecimens of the spinal cord were obtained from the lumbar region in eight sALS patients and age-matched five controls after postmortem examinations. The specimens were double stained with anti-Pin1 and anti-TAR DNA-binding protein of 43 kDa (TDP-43) antibodies, and examined under a fluorescence microscope.ResultsThis study analyzed 254 and 422 spinal motor neurons from 8 sALS patients and 5 control subjects, respectively. The frequency of motor neurons with high cytoplasmic Pin1 expression from the spinal cord did not differ significantly between sALS specimens without cytoplasmic TDP-43 inclusions and control specimens. However, in sALS specimens, neurons for which the Pin1 immunoluminescence intensity in the cytoplasm was at least twice that in the background were more common in specimens with cytoplasmic TDP-43 inclusions (p<0.05 in χ2 test).ConclusionsIn sALS, neurons with higher expression levels of Pin1 levels had more TDP-43 inclusions. Despite the feedback mechanism between Pin1 and ADAR2 being unclear, since Pin1 positively regulates ADAR2, our results suggest that higher Pin1 expression levels in motor neurons with TDP-43 pathology from sALS patients represent a compensatory mechanism. 相似文献
125.
126.
Yosuke Ando Takahiro Hayashi Kaori Ito Eri Suzuki Naoyuki Mine Ayumi Miyamoto Miyuki Oya Hidezo Matsuda Ami Isaji Toru Nakanishi Kazuyoshi Imaizumi Tomoyuki Shibata Tatsuyoshi Okada Kazuo Sakurai Kensei Naito Ichiro Uyama Kenji Kawada Hiroshi Takahashi Shigeki Yamada 《Supportive care in cancer》2016,24(2):871-878
127.
Impact of the Charlson comorbidity index and prognostic nutritional index on prognosis in patients with early gastric cancer after endoscopic submucosal dissection 下载免费PDF全文
Naoto Iwai Osamu Dohi Yuji Naito Yutaka Inada Akifumi Fukui Shun Takayama Kazuyuki Ogita Kei Terasaki Takahiro Nakano Tomohiro Ueda Tetsuya Okayama Naohisa Yoshida Kazuhiro Katada Kazuhiro Kamada Kazuhiko Uchiyama Takeshi Ishikawa Osamu Handa Tomohisa Takagi Hideyuki Konishi Nobuaki Yagi Yoshito Itoh 《Digestive endoscopy》2018,30(5):616-623
128.
129.
Novel ex vivo training model for freehand insertion using a double‐bending peroral direct cholangioscope 下载免费PDF全文