全文获取类型
收费全文 | 9081篇 |
免费 | 435篇 |
国内免费 | 49篇 |
专业分类
耳鼻咽喉 | 83篇 |
儿科学 | 228篇 |
妇产科学 | 219篇 |
基础医学 | 1101篇 |
口腔科学 | 218篇 |
临床医学 | 540篇 |
内科学 | 2006篇 |
皮肤病学 | 174篇 |
神经病学 | 550篇 |
特种医学 | 536篇 |
外科学 | 1598篇 |
综合类 | 52篇 |
预防医学 | 184篇 |
眼科学 | 497篇 |
药学 | 574篇 |
中国医学 | 13篇 |
肿瘤学 | 992篇 |
出版年
2023年 | 63篇 |
2022年 | 128篇 |
2021年 | 202篇 |
2020年 | 98篇 |
2019年 | 130篇 |
2018年 | 189篇 |
2017年 | 135篇 |
2016年 | 206篇 |
2015年 | 181篇 |
2014年 | 251篇 |
2013年 | 295篇 |
2012年 | 492篇 |
2011年 | 591篇 |
2010年 | 308篇 |
2009年 | 278篇 |
2008年 | 508篇 |
2007年 | 525篇 |
2006年 | 538篇 |
2005年 | 535篇 |
2004年 | 515篇 |
2003年 | 441篇 |
2002年 | 479篇 |
2001年 | 220篇 |
2000年 | 219篇 |
1999年 | 238篇 |
1998年 | 106篇 |
1997年 | 100篇 |
1996年 | 83篇 |
1995年 | 76篇 |
1994年 | 76篇 |
1993年 | 66篇 |
1992年 | 127篇 |
1991年 | 115篇 |
1990年 | 92篇 |
1989年 | 108篇 |
1988年 | 90篇 |
1987年 | 103篇 |
1986年 | 121篇 |
1985年 | 84篇 |
1984年 | 68篇 |
1983年 | 43篇 |
1981年 | 27篇 |
1980年 | 22篇 |
1979年 | 31篇 |
1978年 | 22篇 |
1977年 | 26篇 |
1975年 | 18篇 |
1974年 | 18篇 |
1970年 | 23篇 |
1969年 | 24篇 |
排序方式: 共有9565条查询结果,搜索用时 15 毫秒
71.
72.
Tissue factor pathway inhibitor can interact with platelets 总被引:3,自引:0,他引:3
Nishioka T Yokota M Hino M Tsuda I Tatsumi N 《Journal of immunological methods》2002,266(1-2):181-184
Tissue factor pathway inhibitor (TFPI) regulates the extrinsic pathway of blood coagulation. However, there is no report on interaction between TFPI and platelets other than that by Tsuji, who found that whole blood anticoagulated with TFPI exhibited remarkable decrease in platelet count. Our study revealed that washed platelets suspended in modified Tyrode's buffer (8 mM CaCl2) containing TFPI exhibit platelet aggregation. However, platelets aggregation was observed without TFPI, but its increase and intensity were slow and weak, compared to that in the presence of TFPI. This aggregation was inhibited by anti-CD41 (anti-GPIIb) antibody. This finding suggested that TFPI promotes platelet aggregation. 相似文献
73.
Ma Q Kobayashi M Sugiura M Ozaki N Nishio K Shiraishi Y Furukawa K Furukawa K Sugiura Y 《Archives of histology and cytology》2003,66(1):37-44
Gangliosides, a family of glycosphingolipids that contain sialic acid, are abundant on the neuronal cell membranes, but their precise functions in the central nervous system remain largely undefined. In a previous study of GalNAc-T(-/-) mice engineered to lack beta1,4-N-acetylgalactos-aminyltransferase (GM2/GD2 synthase) to abolish any, complex gangliosides, we observed the reduction of nerve conduction velocity but did not find any obvious morphological change in the brain. In the present study, we observed morphological changes in the nerve fiber tracts of the spinal cord in these mice. In GalNAc-T(-/-) mice, the number of degenerated axons was markedly increased in the dorsal funiculus, tract of Lissauer, and dorsolateral funiculus of the cervical segment of the spinal cord as well as the dorsal funiculus and tract of Lissauer of the lumbar segment of the spinal cord. There were also increased numbers of unmyelinated fibers in GalNAc-T(-/-) mice. Loosened myelin sheaths and myelin sheaths separated from axons by wide spaces were also observed in GalNAc-T(-/-) mice. These results provide a morphological basis for the previously observed reduction in the nerve conduction velocity and suggest that complex gangliosides are essential for the maintenance of myelin and the integrity of nerve fibers of the spinal cord. 相似文献
74.
Takai N Miyazaki T Nishida M Nasu K Miyakawa I 《International journal of molecular medicine》2003,12(3):349-354
75.
Keiko Wakui Toshiro Nishida Jun-ichiro Masuda Takeshi Itoh Daisuke Katsumata Tsutomu Ohno Yoshimitsu Fukushima 《Journal of human genetics》1991,36(2):149-153
We report a malformed female infant withde novo interstitial deletion of 4q[46,XX,del(4)(q27q28.2)]. The MN blood type analysis of the family members showed that the patient had an intact blood group-MN locus. The locus of the gene responsible for the MN antigen activity is confined to a 4q28.2–4q31.1 segment on the basis of the result of this patient and the previous mapping data. 相似文献
76.
McCuskey RS Ekataksin W LeBouton AV Nishida J McCuskey MK McDonnell D Williams C Bethea NW Dvorak B Koldovsky O 《The anatomical record. Part A, Discoveries in molecular, cellular, and evolutionary biology》2003,275(1):1019-1030
The development of hepatic microvascular heterogeneity after birth, and its temporal relationship to the development of parenchymal cell plates have received little attention. As a result, the morphogenesis of some of the parameters contributing to this heterogeneity in suckling and weaned rats was studied as a function of time between postpartum days 4 and 30 using in vivo light microscopic, electron microscopic, and immunocytochemical methods. During the early suckling period, the sinusoid network is highly anastomotic, with little evidence of zonation, and the parenchymal cell plates contain multiple cells and are irregularly arranged throughout the lobule. Sinusoidal endothelial fenestration is sparse at 4 days, but phagocytic Kupffer cell (KC) function already exists and exhibits zonal heterogeneity, with more cells located in the periportal zone. With increasing age, endothelial fenestrae increase and organize as sieve plates. Widened centrilobular radial sinusoids form through a loss ("drop-out") of intersinusoidal sinusoids (ISS). Concomitantly, the associated cell plates straighten and become one cell thick. Hepatocyte DNA synthesis and mitosis are higher in the periportal zone, which retains thickened cell plates and anastomotic sinusoids. The centrilobular sinusoids may widen to accommodate the increased volume of blood that results from the loss of ISS as well as the increased numbers of periportal sinusoids containing flow that feed these vessels. KC phagocytic activity increases during the suckling period concomitant with an increase of gut-derived endotoxin in the portal blood, which suggests that the KCs may be releasing mediators that affect sinusoid diameter, blood flow, endothelial fenestration, and perhaps parenchymal growth either directly or through the stimulation of growth factors. 相似文献
77.
Susumu Matsukuma Masateru Doi Masatoshi Suzuki Kazuya Ikegawa Kimiya Sato Noriyuki Kuwabara 《Pathology international》1997,47(11):789-793
A unique case of duodenal stromal tumor In a 51-year-old man is reported. The tumor histologically showed spindle cell proliferation and numerous eosinophilic globules. Most globules were composed of tangled 45 nm thick fibrils, which were ultrastructurally Identical to 'skelnoid fibers'. The presence of glycogen granules in the tumor cells and the Immunoreactivity for α-smooth muscle actin suggested smooth muscle differentiation. Focal ultrastructural findings also supported the smooth muscle nature of this tumor. There were no immunohistochemical and ultra-structural features indicating neural differentiation. In previous studies, the presence of such 'skeinoid fibers' was suggested to be a histological marker for neural differentiation in gastrointestinal stromal tumor. However, the findings In the present case suggest that numerous 'skeinoid fibers' can be Identified in duodenal stromal tumor with smooth muscle differentiation, although this condition may be rare. 相似文献
78.
Shibahara M Nishida K Asahara H Yoshikawa T Mitani S Kondo Y Inoue H 《Acta medica Okayama》2000,54(2):67-74
We investigated the presence of osteocyte apoptosis in the necrotic trabeculae of the femoral head of spontaneously hypertensive rat (SHR) using the in situ nick end labeling (TUNEL) method and transmission electron microscopy. The occurrence of osteonecrosis and ossification disturbance was significantly higher in SHR compared with Wistar Kyoto (WKY) rats, and Wistar (WT) rats used as control animals (P < 0.01). A high population of TUNEL positive osteocytes was detected mainly in 10- and 15-week-old SHRs. Sectioned examination of the femoral head of SHRs and WKY rats by electron microscopy revealed apoptotic cell appearances such as aggregation of chromatin particles and lipid formation. In contrast, a positive reaction was significantly lower in osteocytes in the femoral heads of WT rats (P < 0.01). Our results indicate that apoptosis forms an important component of the global pathologic process affecting the femoral head of SHR, which leads to osteonecrosis in this region. 相似文献
79.
80.
Yasuhiro Nishida Atsuro Miyata Hironobu Morita Nobuhisa Uemura Kenji Kangawa Hisayuki Matsuo Hiroshi Hosomi 《Pflügers Archiv : European journal of physiology》1988,412(5):535-540
We examined in detail changes in arterial plasma ANP concentration in response to volume load in conscious dogs. In a 5-min volume load experiment, 18 ml/kg of isosmotic and isooncotic 3% Dextran 40 in saline was infused over a period of 5 min. Mean left atrial pressure (MLAP) increased transiently by 7.6±0.9 mm Hg. Plasma ANP level (P-ANP) did not significantly increase. Assayed P-ANP levels were corrected for hemodilution. Corrected P-ANP (C-ANP) significantly increased from 206±17 to 348±34 pg/ml. However, the level of C-ANP did not reach a steady state. No significant linear correlation was found between increases in MLAP and normalized C-ANP. In a 45-min volume load experiment, the elevated level of MLAP caused by the 5-min volume load was maintained for 40 min by supplemental infusion. C-ANP significantly increased from 196±18 pg/ml to 435±73 ng/ml. The level of C-ANP reached a steady state. A close linear correlation was observed between increases in MLAP and normalized C-ANP. However, the peak time of C-ANP lagged 10 min behind MLAP. These results indicate that it takes 10 min for P-ANP to reach a steady state in fully responding to a volume load, and that the long-term volume load is a prerequisite to the response of the ANP providing system. 相似文献