全文获取类型
收费全文 | 15967篇 |
免费 | 841篇 |
国内免费 | 79篇 |
专业分类
耳鼻咽喉 | 103篇 |
儿科学 | 235篇 |
妇产科学 | 242篇 |
基础医学 | 1930篇 |
口腔科学 | 336篇 |
临床医学 | 1059篇 |
内科学 | 4131篇 |
皮肤病学 | 266篇 |
神经病学 | 1145篇 |
特种医学 | 686篇 |
外科学 | 2893篇 |
综合类 | 62篇 |
一般理论 | 3篇 |
预防医学 | 362篇 |
眼科学 | 201篇 |
药学 | 1175篇 |
中国医学 | 41篇 |
肿瘤学 | 2017篇 |
出版年
2023年 | 119篇 |
2022年 | 237篇 |
2021年 | 384篇 |
2020年 | 234篇 |
2019年 | 311篇 |
2018年 | 390篇 |
2017年 | 273篇 |
2016年 | 340篇 |
2015年 | 333篇 |
2014年 | 427篇 |
2013年 | 537篇 |
2012年 | 835篇 |
2011年 | 978篇 |
2010年 | 510篇 |
2009年 | 435篇 |
2008年 | 791篇 |
2007年 | 808篇 |
2006年 | 779篇 |
2005年 | 728篇 |
2004年 | 812篇 |
2003年 | 749篇 |
2002年 | 711篇 |
2001年 | 489篇 |
2000年 | 468篇 |
1999年 | 462篇 |
1998年 | 175篇 |
1997年 | 137篇 |
1996年 | 128篇 |
1995年 | 119篇 |
1994年 | 114篇 |
1993年 | 82篇 |
1992年 | 263篇 |
1991年 | 207篇 |
1990年 | 229篇 |
1989年 | 270篇 |
1988年 | 261篇 |
1987年 | 254篇 |
1986年 | 220篇 |
1985年 | 218篇 |
1984年 | 127篇 |
1983年 | 118篇 |
1982年 | 50篇 |
1979年 | 104篇 |
1978年 | 65篇 |
1977年 | 47篇 |
1974年 | 43篇 |
1972年 | 52篇 |
1971年 | 53篇 |
1970年 | 47篇 |
1969年 | 57篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
Takuya Toyama Norihiko Ohura Masakazu Kurita Akira Momosawa Kiyonori Harii 《Nordisk plastikkirurgisk forening [and] Nordisk klubb for handkirurgi》2006,40(6):329-334
We have investigated the effects of short-contact topical application of tretinoin using 16 male db/db mice by creating two full-thickness wounds on the skin of the back. A 0.1% tretinoin aqueous gel was applied to one wound for five minutes daily for five successive days while only aqueous gel was applied to the other (control). The mean (SD) percentage surface area unhealed before and after treatment were 0.88 (0.3) and 0.64 (0.15). In tretinoin-treated mice and non-treated mice (controls), the mean (SD) thicknesses of granulation were 1.383 (697) micro m and 683 (413) micro m, the density of capillary vessels in granulation was 12.2 (5.5)% and 5.7 (3.9)%, respectively. Differences between the two groups were significant for each variable. Wound healing was accelerated with short-contact topical application of tretinoin in db/db mice. 相似文献
14.
Resolution of homonymous visual field loss documented with functional magnetic resonance and diffusion tensor imaging. 总被引:5,自引:0,他引:5
Masaki Yoshida Masahiro Ida Thien Huong Nguyen Marie-Therese Iba-Zizen Luc Bellinger Jean Louis Stievenart Takehiko Nagao Shinsuke Kikuchi Takaaki Hara Takuya Shiba Kenji Kitahara Emmanuel Alain Cabanis 《Journal of neuro-ophthalmology》2006,26(1):11-17
A 68-year-old man developed right homonymous hemianopic paracentral scotomas from acute infarction of the left extrastriate area. He was studied over the ensuing 12 months with visual fields, conventional MRI, functional MRI (fMRI), and diffusion tensor imaging (DTI). As the visual field defect became smaller, fMRI demonstrated progressively larger areas of cortical activation. DTI initially showed that the lesioned posterior optic radiations were completely interrupted. This interruption lessened in time and had disappeared by one year after onset. fMRI and DTI are innovative measures to follow functional and structural recovery in the central nervous system. This is the first reported application of these imaging techniques to acute cerebral visual field disorders. 相似文献
15.
J T Fujii 《The Journal of comparative neurology》1992,316(3):279-286
The avian Edinger Westphal nucleus, through the ciliary ganglion, controls accommodation, iris constriction, and blood flow through the choroid. In live brainstem slices, the nucleus is easily identifiable as an olive-shaped cluster of neurons dorsal to the oculomotor nerve and nucleus. Intracellular recordings from neurons in the nucleus identified two classes of responses to sustained (300 to 500 ms) injections of depolarizing current. One set of cells fired action potentials for the duration of the pulse while a second set of cells fired action potentials only transiently, during the first 50 to 100 ms, after which they remained silent regardless of the size of the depolarization. Intracellular recordings followed by injections of the fluorescent dye lucifer yellow revealed that repetitively firing cells were located in the lateral half of the nucleus while non-repetitively or transiently firing cells were located in the medial half. These locations correspond to different Edinger Westphal subdivisions which have distinct inputs and target populations. The varying firing patterns are discussed with reference to the known functions of the subdivisions in which they occur. Replacement of calcium by magnesium in the extracellular medium had no effect on the number of action potentials fired by non-repetitively firing cells, suggesting that a calcium-activated potassium current is not responsible for suppressing repetitive firing in these cells. In contrast, in repetitively firing cells removal of extracellular calcium increased the frequency of action potential discharge and decreased the amplitude of afterhyperpolarizations following single action potentials. Addition of cadmium to the bath medium had similar effects.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
16.
Takakura Yoshinobu Fujita Takuya Hashida Mitsuru Sezaki Hitoshi 《Pharmaceutical research》1990,7(4):339-346
As part of the strategy for the design of macromolecular carriers for drug targeting, the disposition characteristics of macromolecules were studied in mice bearing tumors that served as target tissues. Eight kinds of macromolecules including four polysaccharides and four proteins with different molecular weights and electric charges were used; tissue distribution and tumor localization after intravenous injection were studied. Pharmacokinetic analysis revealed that the tissue radioactivity uptake rate index calculated in terms of clearance was different among the tested compounds; especially, the urinary radioactivity excretion clearances and the total hepatic radioactivity uptake clearances varied widely. Compounds with low molecular weights (approximately 10 kD) or positive charges showed lower tumor radioactivity accumulation; radioactivity was rapidly eliminated from the plasma via rapid urinary excretion or extensive hepatic uptake, respectively. On the other hand, large and negatively charged compounds, carboxymethyl dextran, bovine serum albumin, and mouse immunoglobulin G, showed higher radioactivity accumulation in the tumor (calculated total amounts were 15.6, 10.8, and 20.8% of the dose, respectively) and prolonged retention in the circulation. These results demonstrated that the total systemic exposure rather than the uptake rate index was correlated with total tumor uptake. Molecular weight and electric charge of the macromolecules significantly affected their disposition characteristics and, consequently, determined radioactivity accumulation in the tumor. It was concluded that a drug–carrier complex designed for systemic tumor targeting should be polyanionic in nature and larger than 70,000 in molecular weight. 相似文献
17.
Shigeki Ohgitani Akimitsu Miyauchi Yasuyuki Takagi Yoshio Fujii Takuo Fujita Misa Nakamura Zhi-qiang Zhang Liang Shan Mitsuyo Sasaki Ryuichi Tsukino Toyoharu Yokoi Kennichi Kakudo Tomitaka Nakayama Junya Toguchida Hiroshi Kanoe Shinichi Aizawa Masao S. Sasaki Takashi Nakamura M. Suda K. Tanaka Y. Ogawa N. Tamura A. Yasoda H. Itoh M. Uehira N. Nishimoto T. Takigawa K. Shiota K. Nakao 《Journal of bone and mineral metabolism》1997,15(3):165-171
18.
H Nakamura H Masutani Y Tagaya A Yamauchi T Inamoto Y Nanbu S Fujii K Ozawa J Yodoi 《Cancer》1992,69(8):2091-2097
Adult T-cell leukemia-derived factor (ADF), originally defined as an interleukin-2 receptor inducer, is a human thioredoxin homologue. ADF is detected in many malignant tissues and has a growth-promoting effect on transformed cells. In this study, ADF expression was examined immunohistochemically in human liver cell lines and liver tissues, and its growth-promoting effect was tested on human hepatoma cells. On three liver cell line--PLC/PRF/5, HepG2, and Chang liver cells--ADF stained positively and also was detected by immunoblotting. ADF had strong staining in the fetal liver (n = 8), although it was faint in the normal adult liver (n = 6). In hepatocellular carcinoma (n = 25), ADF expression generally was enhanced and was very strong in 52% (13 of 25) of the cases, although it was moderate in cases of chronic hepatitis or cirrhosis. ADF augmented the growth of PLC/PRF/5 cells and showed an additive effect with epidermal growth factor. These results indicate possible involvement of ADF in cell activation and growth of hepatocytes, as is the case with lymphocytes. 相似文献
19.
20.
W E Hopkins D R Westerhausen S Fujii J J Billadello B E Sobel 《Thrombosis and haemostasis》1991,66(2):239-245
Plasminogen activator inhibitor type-1 (PAI-1) is a physiologic modulator of the fibrinolytic system. We have shown previously that PAI-1 biosynthesis in cultured cells depends on several factors in serum. Because platelets are richly endowed with specific growth factors and because the release reaction is an integral part of thrombosis, the present study was performed to determine whether platelets augment PAI-1 production and if so, to define mediators responsible. Hep G2 cells were used to determine whether platelet lysates increased PAI-1 synthesis in a dose and time-dependent manner. In cells labeled metabolically with 35S-methionine for 6 h, an increase in labeled PAI-1 was elicited indicative of de novo synthesis as well as increased secretion of PAI-1 mediated by platelet lysates. Steady state levels of both the 3.2 and 2.2 kb forms of PAI-1 mRNA increased after 2 h and peaked in 3-5 h in a dose-dependent fashion as well. Incubation of Hep G2 cells with collagen activated platelets resulted in a similar induction of PAI-1 mRNA. The increase in PAI-1 mRNA occurred with exposure of the cells to platelet lysates for intervals as brief as 15 min and was not inhibited by cycloheximide indicating its independence of new protein synthesis. In order to identify the factors in platelets responsible for the induction of PAI-1 synthesis in the Hep G2 cell model system, neutralizing antibodies were used to inhibit specific platelet associated growth factors. Antibodies to transforming growth factor-beta (TGF-beta) and to the epidermal growth factor (EGF)/transforming growth factor alpha (TGF-alpha) receptor inhibited the platelet lysate-mediated increase in PAI-1 protein by 77%.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献