全文获取类型
收费全文 | 36003篇 |
免费 | 1838篇 |
国内免费 | 150篇 |
专业分类
耳鼻咽喉 | 486篇 |
儿科学 | 653篇 |
妇产科学 | 437篇 |
基础医学 | 4491篇 |
口腔科学 | 1183篇 |
临床医学 | 2493篇 |
内科学 | 8075篇 |
皮肤病学 | 790篇 |
神经病学 | 3372篇 |
特种医学 | 1871篇 |
外国民族医学 | 1篇 |
外科学 | 5668篇 |
综合类 | 130篇 |
一般理论 | 6篇 |
预防医学 | 1086篇 |
眼科学 | 762篇 |
药学 | 2388篇 |
中国医学 | 78篇 |
肿瘤学 | 4021篇 |
出版年
2023年 | 167篇 |
2021年 | 606篇 |
2020年 | 356篇 |
2019年 | 462篇 |
2018年 | 594篇 |
2017年 | 494篇 |
2016年 | 640篇 |
2015年 | 598篇 |
2014年 | 790篇 |
2013年 | 967篇 |
2012年 | 1602篇 |
2011年 | 1653篇 |
2010年 | 1016篇 |
2009年 | 838篇 |
2008年 | 1470篇 |
2007年 | 1732篇 |
2006年 | 1593篇 |
2005年 | 1532篇 |
2004年 | 1567篇 |
2003年 | 1460篇 |
2002年 | 1526篇 |
2001年 | 1326篇 |
2000年 | 1430篇 |
1999年 | 1293篇 |
1998年 | 485篇 |
1997年 | 401篇 |
1996年 | 375篇 |
1995年 | 310篇 |
1994年 | 314篇 |
1993年 | 285篇 |
1992年 | 994篇 |
1991年 | 854篇 |
1990年 | 824篇 |
1989年 | 811篇 |
1988年 | 769篇 |
1987年 | 764篇 |
1986年 | 669篇 |
1985年 | 626篇 |
1984年 | 433篇 |
1983年 | 350篇 |
1979年 | 302篇 |
1978年 | 205篇 |
1977年 | 178篇 |
1974年 | 196篇 |
1973年 | 163篇 |
1972年 | 162篇 |
1971年 | 181篇 |
1970年 | 155篇 |
1969年 | 176篇 |
1968年 | 147篇 |
排序方式: 共有10000条查询结果,搜索用时 187 毫秒
991.
Atsushi Kurata Shigeru Inoue Shin-ichiro Ohno Ryosuke Nakatsubo Kengo Takahashi Tatsuya Ito Kenta Kawasaki Reiji Kokubo Takashi Sakai Jun Ubukata Shuya Matsubara Ryu Muraoka Jun Yamazaki Takao Hirose Mayuko Hojo Eri Watanabe Masahiko Kuroda 《Pathology, research and practice》2013
Although the presence of renal cysts has been reported to be associated with aortic aneurysm or dissection by imaging studies, an autopsy study has not been performed. Therefore, in our institute, recent consecutive adult autopsy cases (n = 108, 64 males and 44 females) were reviewed. The circumferences and atherosclerosis ratios of both thoracic and abdominal aorta were individually measured and graded. The number of renal cysts was scored and graded. Age of subjects along with histories of smoking, hypertension, and diabetes mellitus were confirmed. Multiple linear regression analyses demonstrated that severity of atherosclerosis and the number of renal cysts were correlated with thoracic aortic circumference, while only the number of renal cysts was correlated with abdominal aortic circumference (p < 0.05), which was more predominant in female subjects (p < 0.05). Microscopically, significantly more dilated renal tubules (by Student's t-test, p < 0.05) along with decreased stainability of basement membrane by Periodic acid-Schiff staining and immunostaining of type IV collagen were noted in background renal tissues in cases with numerous renal cysts than in age- and sex-matched controls without renal cysts (n = 10 vs. 10). The present study suggests that a syndrome that affects both aorta and renal tubules may exist. 相似文献
992.
Lamotte Guillaume Takahashi Makoto Wu Tianxia Sullivan Patricia Cherup Jamie Holmes Courtney Goldstein David S. 《Clinical autonomic research》2021,31(4):543-551
Clinical Autonomic Research - Patients with neurogenic orthostatic hypotension in the setting of Lewy body diseases (LBnOH) typically have baroreflex failure and peripheral noradrenergic... 相似文献
993.
Akira Endo Hirotaka Koizumi Makiko Takahashi Tomohiro Tamura Shinobu Tatsunami Yoshiyuki Watanabe Masayuki Takagi 《Virchows Archiv : an international journal of pathology》2013,462(2):131-139
Sessile serrated adenoma/polyps (SSA/Ps) of the colon are thought to be precursors of sporadic carcinomas. Although it is suggested that SSA/P may grow rapidly from the early stage, its cell kinetics remains obscure. To solve this problem, we analyzed the mitotic and apoptotic activity of normal crypts, microvesicular hyperplastic polyps (MVHPs), and tubular adenomas (TAs), using phospho-histone H3 and cleaved caspase 3 immunohistochemistry. The mitotic index for SSA/Ps (mean, 5.63) and TAs (6.98) was significantly higher than those for normal crypts (2.72) and MVHPs (2.86). Of all tested lesions, the apoptotic index was lowest for SSA/Ps (0.96; normal, 2.71; MVHPs, 2.62; TAs, 6.01) with statistically significant differences. The net growth ratio was close to 1.0 in normal crypts (1.07) while remaining low in MVHPs (1.06) and TAs (1.38), but was markedly elevated in SSA/Ps (7.32, P?<?0.01) due to the large imbalance between mitosis and apoptosis. As to apoptosis regulatory proteins, expression of anti-apoptotic Bcl-2 was significantly reduced or undetectable in MVHPs and SSA/Ps, while TAs showed stronger staining than normal crypts. Expression of pro-apoptotic Bax and its activators, Bim and Bad, was significantly reduced in MVHPs and SSA/Ps. We suggest that other complex mechanisms may act synergistically with Bax, Bim, or Bad deficiency to regulate apoptosis suppression in SSA/Ps. 相似文献
994.
995.
Naoki Takahashi Kiyokazu Kametani Ryo Ota Prasarn Tangkawattana Tomohito Iwasaki Yasuhiro Hasegawa Hiromi Ueda Marina Hosotani Takafumi Watanabe 《Journal of anatomy》2021,238(1):63-72
Tendons transmit force from muscle to bone for joint movement. Tenocytes are a specialized type of fibroblast that produces collagen fibrils in tendons. Their cytoplasmic processes form a network surrounding collagen fibrils to define a collagen fibre. Glycosaminoglycan (GAG) chains link collagen fibrils and adhere at the D-band of the collagen fibril. In this study, we used array and scanning transmission electron microscope (STEM) tomographies to reconstruct the three-dimensional ultrastructure of tenocytes, collagen fibres, collagen fibrils and GAG chains at the bifurcation of the bovine hindlimb superficial digital flexor tendon (SDFT). Collagen fibrils comprising a collagen fibre were not aligned uniformly and had at least two running directions. Spindle-shaped tenocytes were arranged along the long axis of a plurality of collagen fibres, where two groups of collagen fibrils with oblique directions to each other exhibited an oblique overlap of the two collagen fibril layers. Collagen fibrils with different running directions were observed in separating layers of about 300 nm in thickness and had diameters of 0–200 nm. About 40% of all collagen fibrils had a peak in the range of 20–40 nm. STEM analysis of the same site where the crossing of collagen fibres was observed by transmission electron microscopy demonstrated the outline of collagen fibrils with a clear D-banding pattern at a regular interval. Collagen fibrils were reconstructed three-dimensionally using continuous images acquired by STEM tomography, which confirmed that the collagen fibrils at the crossing sites did not orientate in layers, but were woven one by one. Higher magnification observation of GAG chains attached between the crossing collagen fibrils revealed numerous GAG chains arranged either vertically or obliquely on collagen fibrils. Furthermore, GAG chains at the cross of collagen fibrils connected the closest D-bands. GAG chains are thought to be universally present between collagen fibrils of the tendon. These observations by array and STEM tomographies increase our knowledge of the anatomy in the bifurcation of the bovine hindlimb SDFT and demonstrate the utility of these new imaging technologies. 相似文献
996.
M.S.S. Buto V. Vassimon-Barroso E. Fiogb A.C.S. Farche B.F. Carnavale P.G. Rossi C.A. Sakaguchi A.M. Catai A.C.M. Takahashi 《Brazilian journal of medical and biological research》2021,54(6)
The aim of this study was to investigate the effects of multicomponent training on baroreflex sensitivity (BRS) and heart rate (HR) complexity of prefrail older adults. Twenty-one prefrail community-dwelling older adults were randomized and divided into multicomponent training intervention group (MulTI) and control group (CG). MulTI performed multicomponent exercise training over 16 weeks and CG was oriented to follow their own daily activities. The RR interval (RRi) and blood pressure (BP) series were recorded for 15 min in supine and 15 min in orthostatic positions, and calculation of BRS (phase, coherence, and gain) and HR complexity (sample entropy) were performed. A linear mixed model was applied for group, assessments, and their interaction effects in supine position. The same test was used to assess the active postural maneuver and it was applied separately to each group considering assessments (baseline and post-intervention) and positions (supine and orthostatic). The significance level established was 5%. Cardiovascular control was impaired in prefrail older adults in supine position. Significant interactions were not observed between groups or assessments in terms of cardiovascular parameters. A 16-week multicomponent exercise training did not improve HR complexity or BRS in supine rest or in active postural maneuver in prefrail older adults. 相似文献
997.
998.
Haruna Yagi Masato Nakaguro Masafumi Ito Yuki Okumura Seishiro Takahashi Yoichiro Aoshima Yasunori Enomoto Shiori Meguro Hideya Kawasaki Isao Kosugi Yoshie Shimoyama Hiroshi Ogawa Hisashi Tateyama Toshihide Iwashita 《Pathology international》2021,71(7):453-462
Micronodular thymoma with lymphoid stroma (MNT) is a rare thymic epithelial neoplasm subtype characterized by a micronodular tumor cell growth pattern and abundant lymphoid stroma. Micronodular thymic carcinoma with lymphoid stroma (MNCA) is considered as a malignant counterpart of MNT and exhibits a growth pattern similar to that of MNT but has histologic features reminiscent of thymic squamous cell carcinoma, such as cytologic atypia and CD5 and CD117 immunoexpression. Although both MNT and MNCA are characterized by abundant lymphoid stroma, it remains unknown whether there are differences in infiltrating lymphocytes between MNT and MNCA. We analyzed the immune microenvironment profile in eight MNT and three MNCA cases. The cell density of CD8-positive T cells was significantly higher in MNT than in MNCA, whereas that of FOXP3-positive T cells was significantly higher in MNCA than in MNT. There was no significant difference in the cell density of programmed death protein 1-positive T cells and programmed death ligand 1 expression between the MNT and MNCA cases. Our findings indicated that the immune microenvironment of MNCA differed from that of MNT and, compared with the T-cell profile of MNT, that of MNCA was more suppressive to patients′ antitumor immune response. 相似文献
999.
Kenta Takahashi Yasunori Sato Minako Yamamura Satoko Nakada Yuko Tamano Motoko Sasaki Kenichi Harada 《Pathology international》2021,71(8):521-529
The Notch signaling pathway plays a key role in the morphogenesis of the biliary tree, but its involvement in cystic biliary diseases, such as Caroli disease (CD) and polycystic liver disease (PLD), has yet to be determined. Immunostaining was performed using liver sections of CD and PLD, and the results were compared with those of congenital hepatic fibrosis (CHF) and von Meyenburg complex (VMC). The expression of Notch receptor 1 (Notch1) was increased in the nuclei of biliary epithelial cells in all cases of CD and PLD, whereas it remained at a low level in CHF and VMC. In addition, Notch2 and Notch3 were preferably expressed in the nuclei of biliary epithelial cells of PLD. Accordingly, the Notch effector Hes1 was highly expressed in biliary epithelial cells of CD and PLD, and the cell proliferative activity was significantly higher in CD and PLD. The expression of the Notch ligand Delta-like 1 was significantly increased in biliary epithelial cells of CD and PLD, which may be causally associated with the nuclear overexpression of Notch1 and Hes1. These results indicate that aberrant activation of the Notch-Hes1 signaling pathway may be responsible for the progression of biliary cystogenesis in CD and PLD. 相似文献
1000.
Hidetaka Seo Hitomi Masuda Kenjiro Asagoshi Tomoaki Uchiki Shigehisa Kawata Goh Sasaki Takashi Yabuki Shunsuke Miyai Naoki Takahashi Shu-ichi Hashimoto Atsushi Sawada Aki Takaiwa Chika Koyama Kanako Tamai Kohei Kurosawa Ke-Yi Lin Kunihiro Ohta Yukoh Nakazaki 《Cellular & molecular immunology》2021,18(6):1545
Monoclonal antibodies (mAbs) are widely utilized as therapeutic drugs for various diseases, such as cancer, autoimmune diseases, and infectious diseases. Using the avian-derived B cell line DT40, we previously developed an antibody display technology, namely, the ADLib system, which rapidly generates antigen-specific mAbs. Here, we report the development of a human version of the ADLib system and showcase the streamlined generation and optimization of functional human mAbs. Tailored libraries were first constructed by replacing endogenous immunoglobulin genes with designed human counterparts. From these libraries, clones producing full-length human IgGs against distinct antigens can be isolated, as exemplified by the selection of antagonistic mAbs. Taking advantage of avian biology, effective affinity maturation was achieved in a straightforward manner by seamless diversification of the parental clones into secondary libraries followed by single-cell sorting, quickly affording mAbs with improved affinities and functionalities. Collectively, we demonstrate that the human ADLib system could serve as an integrative platform with unique diversity for rapid de novo generation and optimization of therapeutic or diagnostic antibody leads. Furthermore, our results suggest that libraries can be constructed by introducing exogenous genes into DT40 cells, indicating that the ADLib system has the potential to be applied for the rapid and effective directed evolution and optimization of proteins in various fields beyond biomedicine. 相似文献