全文获取类型
收费全文 | 7851篇 |
免费 | 523篇 |
国内免费 | 51篇 |
专业分类
耳鼻咽喉 | 32篇 |
儿科学 | 124篇 |
妇产科学 | 98篇 |
基础医学 | 1140篇 |
口腔科学 | 160篇 |
临床医学 | 709篇 |
内科学 | 2236篇 |
皮肤病学 | 257篇 |
神经病学 | 383篇 |
特种医学 | 270篇 |
外科学 | 1271篇 |
综合类 | 31篇 |
一般理论 | 1篇 |
预防医学 | 227篇 |
眼科学 | 86篇 |
药学 | 473篇 |
中国医学 | 21篇 |
肿瘤学 | 906篇 |
出版年
2023年 | 52篇 |
2022年 | 93篇 |
2021年 | 193篇 |
2020年 | 75篇 |
2019年 | 134篇 |
2018年 | 184篇 |
2017年 | 116篇 |
2016年 | 165篇 |
2015年 | 146篇 |
2014年 | 215篇 |
2013年 | 260篇 |
2012年 | 416篇 |
2011年 | 431篇 |
2010年 | 232篇 |
2009年 | 213篇 |
2008年 | 381篇 |
2007年 | 366篇 |
2006年 | 380篇 |
2005年 | 377篇 |
2004年 | 367篇 |
2003年 | 373篇 |
2002年 | 285篇 |
2001年 | 269篇 |
2000年 | 304篇 |
1999年 | 279篇 |
1998年 | 101篇 |
1997年 | 76篇 |
1996年 | 73篇 |
1995年 | 57篇 |
1994年 | 55篇 |
1993年 | 72篇 |
1992年 | 185篇 |
1991年 | 189篇 |
1990年 | 183篇 |
1989年 | 165篇 |
1988年 | 142篇 |
1987年 | 109篇 |
1986年 | 90篇 |
1985年 | 95篇 |
1984年 | 70篇 |
1983年 | 49篇 |
1982年 | 24篇 |
1981年 | 29篇 |
1980年 | 23篇 |
1979年 | 44篇 |
1978年 | 22篇 |
1977年 | 28篇 |
1976年 | 25篇 |
1970年 | 22篇 |
1968年 | 22篇 |
排序方式: 共有8425条查询结果,搜索用时 15 毫秒
51.
52.
T. Kobayashi F.A. Neethling S. Taniguchi Y. Ye M. Niekrasz E. Koren W.W. Hancock H. Takagi D.K.C. Cooper 《Xenotransplantation》1996,3(3):237-245
Abstract: We examined whether hyperacute rejection (HAR) of a discordant xenograft in a nonhuman primate model could be inhibited by the anticomplement agents, FUT-175 (FUT) and K76COOH (K76). The inhibitory effect of FUT and K76 on baboon sera was studied in vitro by i) complement-mediated hemolysis of sheep erythrocytes (by measuring serum CH50) and ii) cytotoxicity to cultured pig kidney (PK15) cells. The in vivo administration of FUT (at 0.2–25 mg/kg/h i.v. continuously) and K76 (50 mg/kg i.v. bolus) allowed evaluation of the serum levels of these drugs. Both FUT and K76 inhibited serum CH50 in a concentration-dependent manner. An enhanced effect was obtained by combining K76 with FUT therapy. High concentrations of FUT (>10-4 M) and K76 (>103 μxg/ml) were necessary to suppress serum CH50 to <5% of the normal level. However, PK15 cytotoxicity remained at >50% in the presence of i) 10-4 M of FUT, ii) 103 μg/ml of K76, and iii) 10-6 M of FUT + 103 μg/ml of K76. Pig heart transplantation (HTX) was performed in two baboons receiving FUT (1 mg/kg/h i.v. continuously) and K76 (at 200 mg/kg ×1 or 400 mg/kg + 200 mg/kg × 2 i.v, respectively). Cytotoxicity of the serum to PK15 cells at the time of HTX showed 39% and 1% cell death, respectively, in these two baboons, and the CH50 level was 1% (of control level) and 0%, respectively. Graft survival was 4.5 hours and 10 hours (with death of the baboon), respectively (compared with a mean of 29 minutes in control experiments). Both excised grafts showed typical features of hyperacute rejection. Immunopathological studies revealed deposition of C1q, C3d, C6, properdin, and Factor B, demonstrating that complement activation was not fully inhibited by FUT and K76. We conclude that i) FUT and K76 are indeed potent complement inhibitors, ii) the dosages of FUT and K76 necessary to suppress complement-mediated injury cannot be extrapolated from previously reported data obtained from serum CH50 levels, and iii) higher (possibly toxic) dosages will be required to inhibit complement activation completely. It seems unlikely that HAR will be prevented by these drugs alone, although they may be beneficial when combined with other forms of therapy. 相似文献
53.
Darik K. Taniguchi MD Roy W. Martin PhD Eugene A. Trowers MPH MD Fred E. Silverstein MD 《Gastrointestinal endoscopy》1995,41(6)
We report the simultaneous measurement of esophageal wall layer thickness and intraluminal pressure in the sheep esophagus using a miniature suction device incorporating a high-frequency ultrasound transducer and a manometry system. Transnasal placement of the device into the distal esophagus of a conscious sheep allowed observation of 133 swallowing events during three trials, each lasting from 45 to 60 minutes. In a fourth trial, 11 sequential dry and 23 sequential wet swallows were compared. Maximum manometric pressure, esophageal wall layer thickness, and duration of contraction were measured. All swallowing events produced simultaneous increases in intraluminal pressure and esophageal wall thickness. Mean maximal pressures were lower for dry swallows (18 ± 2.1 mm Hg) than wet swallows (22 ± 3.0 mm Hg) (p < .01). Thickness of the inner (circular) muscle layer increased above baseline by 124% for dry swallows and 161% for wet swallows (p < .01). We conclude that thickening of the esophageal inner (circular) muscle layer may be important in the generation of intraluminal esophageal pressure in the sheep esophagus. (Gastrointest Endosc 1995;41:582-6.) 相似文献
54.
Yuta Ishizuka Yasushi Ishida Qing-Hua Jin Ayumi Shimokawa Mitsuhiko Saita Kazuo Kato Takato Kunitake Takamitsu Hanamori Yoshio Mitsuyama Hiroshi Kannan 《Brain research》1998,789(1):10
Nitric oxide (NO) has recently been shown to modulate the hypothalamic–pituitary–adrenal axis response to interleukin-1β (IL-1β). We measured levels of nitrite (NO2−) and nitrate (NO3−) in the hypothalamic paraventricular nucleus (PVN) region using an in vivo brain microdialysis technique in conscious rats. Intraperitoneally administered IL-1β produced a significant increase in both NO2− and NO3− levels in the PVN region. We also examined the possible involvement of the abdominal vagal afferent nerves in this effect. In abdominal-vagotomized rats, the increase was significantly attenuated compared to that in sham-operated rats. Our results suggest that the abdominal vagal afferent nerves are involved in intraperitoneally administered IL-1β-induced NO release in the PVN region. 相似文献
55.
S Kobayashi S Kitamura K Kawachi T Nishii S Taniguchi M Fukutomi K Mizuguchi Y Hamada J Hasegawa 《Kyobu geka. The Japanese journal of thoracic surgery》1989,42(6):453-456
The newly developed oxygenator "D702" is a compact hollow fiber membrane oxygenator with a priming volume of 170 ml. The maximum flow allowance is 4 liters per/minute. We used this oxygenator in 16 patients (11 infants and children, and 5 adults) undergoing various open heart surgery, and function of this oxygenator was studied. Pulsatile cardiopulmonary bypass was performed in 8 patients and nonpulsatile constant flow perfusion was employed in the remaining 8 patients. Our clinical experience showed excellent maintenance of PaO2 and PaCO2 during both pulsatile and constant flow bypasses. A low pressure drop was encountered across the membrane oxygenator, and therefore, this oxygenator is applicable for pulsatile cardiopulmonary bypass. The D702 is a very useful and applicable for a wide range of patients from infants to adults with a small body structure. 相似文献
56.
Possible involvement of arachidonic acid metabolism in phenobarbital promotion of hepatocarcinogenesis 总被引:8,自引:4,他引:4
Denda Ayumi; Ura Hitoshi; Tsujiuchi Toshifumi; Masahiro Tsutsumi; Eimoto Hiroyuki; Takashima Yoshiharu; Kitazawa Shunji; Kinugasa Tetsuo; Konishi Yoich 《Carcinogenesis》1989,10(10):1929-1935
The effects of inhibitors of arachidonic acid metabolism andantioxidants on the rat liver tumor promotion activity of phenobarbital(PB) were assessed using the enzyme-altered focus as the end-pointlesion. Fischer 344 male rats were initiated with N-nitrosodiethylamine(200 mg/kg) and then divided into five groups placed on basaldiet, diet containing 0.05% PB, diet containing 0.05% PB plus0.75%, 1% or 1.5% levels of various inhibitors of arachidonicacid metabolism or antioxidants, or diet containing 1% or 1.5%inhibitors or antioxidants alone for 10 weeks, and then killed.-Bromo phenacyl bromide, an inhibitor of phospholipase A2 significantly inhibited the promotion activity of PB at dose levelsof 0.75% and 1.5%, reaching plateau at 0.75%. Both quercetin,an inhibitor of lipoxygenase, and morin, a dual inhibitor oflipoxygenase-cyclooxygenase, significantly reduced the promotionactivity of PB at the 1.5% but not 0.75% dose levels. Moreover,acetylsalicylic acid, an inhibitor of cyclooxygenase dose-dependentlyinhibited the promotion activity of PB. Among the antioxidantsinvestigated, vitamin E did not affect, but n-propyl gallateand ethoxyquin exerted a dose-dependent inhibition of PB promotion.These results are strongly suggestive of an involvement of phospholipaseA2 lipoxygenase and cyclooxygenase arachidonic acid metabolicpathways in the mechanisms underlying PB enhancement of hepatocarcinogenesis. 相似文献
57.
Interleukin 2 (IL2) is assigned to human chromosome 4 总被引:31,自引:0,他引:31
T. Shows R. Eddy L. Haley M. Byers M. Henry T. Fujita H. Matsui T. Taniguchi 《Somatic Cell and Molecular Genetics》1984,10(3):315-318
The human gene for interleukin 2 (IL2)was assigned to chromosome 4 using human-mouse somatic cell hybrids and Southern filter hybridization of cell hybrid DNA. To identify IL2,a recombinant DNA probe (pIL2-50A) was used which contained a human interleukin 2 cDNA insert which hybridized to a 3.5-kb fragment in human DNA when cleaved with the restriction enzyme EcoRL. 相似文献
58.
59.
Fukui K Kominami R Kaneuji A Matsumoto T Shinohara H 《Okajimas folia anatomica Japonica》2004,81(4):57-62
We report a new method of perfusion fixation for the proximal one-third of the femur of the Japanese white rabbit. Fluids to flush the blood and fix the marrow were injected into the abdominal aorta and drained from the stump of the femur. The oozing of the fluids from the stumps guaranteed complete flushing and fixation. The new method facilitated fixation and decreased the volume of necessary fluids. Scanning electron microscopy (SEM) images of bone marrow fixed using the new method and using the conventional method did not differ. Large fat globules were not observed in the SEM specimens produced using either the new or the conventional method. 相似文献
60.
Focal hyperplasia of intracytoplasmic filaments of 100A in diameter was observed within chief cells of the parathyroid gland in dogs treated with nalidixic acid. The structure, as a rule, was located in the neighborhood of the nucleus and no other cell organelles were detected within it. Its size had a wide spectrum from a small part of the cytoplasm to as large as half a cell. Golgi apparatus and rough endoplasmic reticulum in the involved cells had a tendency to atrophy. These cells occasionally contained less secretory granules. Lipid droplets are diffusely increased. The pathogenesis and significance of the present intracytoplasmic filaments remain to be determined. However, as lipid deposition, atrophy of Golgi apparatus, poorly developed rough endoplasmic reticulum occur in a hypofunctional or degenerative state, it might be possible that filamentous hyperplasia is closely associated with that state. 相似文献