全文获取类型
收费全文 | 10830篇 |
免费 | 528篇 |
国内免费 | 45篇 |
专业分类
耳鼻咽喉 | 102篇 |
儿科学 | 216篇 |
妇产科学 | 169篇 |
基础医学 | 1265篇 |
口腔科学 | 266篇 |
临床医学 | 677篇 |
内科学 | 2847篇 |
皮肤病学 | 224篇 |
神经病学 | 615篇 |
特种医学 | 267篇 |
外科学 | 1985篇 |
综合类 | 39篇 |
预防医学 | 257篇 |
眼科学 | 240篇 |
药学 | 883篇 |
中国医学 | 35篇 |
肿瘤学 | 1316篇 |
出版年
2023年 | 41篇 |
2022年 | 86篇 |
2021年 | 166篇 |
2020年 | 86篇 |
2019年 | 123篇 |
2018年 | 178篇 |
2017年 | 124篇 |
2016年 | 214篇 |
2015年 | 207篇 |
2014年 | 261篇 |
2013年 | 328篇 |
2012年 | 530篇 |
2011年 | 509篇 |
2010年 | 293篇 |
2009年 | 279篇 |
2008年 | 518篇 |
2007年 | 552篇 |
2006年 | 522篇 |
2005年 | 597篇 |
2004年 | 566篇 |
2003年 | 569篇 |
2002年 | 589篇 |
2001年 | 448篇 |
2000年 | 414篇 |
1999年 | 369篇 |
1998年 | 139篇 |
1997年 | 135篇 |
1996年 | 105篇 |
1995年 | 98篇 |
1994年 | 102篇 |
1993年 | 84篇 |
1992年 | 223篇 |
1991年 | 195篇 |
1990年 | 175篇 |
1989年 | 183篇 |
1988年 | 155篇 |
1987年 | 155篇 |
1986年 | 130篇 |
1985年 | 141篇 |
1984年 | 109篇 |
1983年 | 85篇 |
1982年 | 41篇 |
1981年 | 38篇 |
1980年 | 37篇 |
1979年 | 61篇 |
1978年 | 42篇 |
1974年 | 37篇 |
1972年 | 43篇 |
1971年 | 50篇 |
1969年 | 38篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
Repair of infarcted myocardium mediated by transplanted bone marrow-derived CD34+ stem cells in a nonhuman primate model 总被引:6,自引:0,他引:6
Yoshioka T Ageyama N Shibata H Yasu T Misawa Y Takeuchi K Matsui K Yamamoto K Terao K Shimada K Ikeda U Ozawa K Hanazono Y 《Stem cells (Dayton, Ohio)》2005,23(3):355-364
Rodent and human clinical studies have shown that transplantation of bone marrow stem cells to the ischemic myocardium results in improved cardiac function. In this study, cynomolgus monkey acute myocardial infarction was generated by ligating the left anterior descending artery, and autologous CD34(+) cells were transplanted to the peri-ischemic zone. To track the in vivo fate of transplanted cells, CD34(+) cells were genetically marked with green fluorescent protein (GFP) using a lentivirus vector before transplantation (marking efficiency, 41% on average). The group receiving cells (n = 4) demonstrated improved regional blood flow and cardiac function compared with the saline-treated group (n =4) at 2 weeks after transplant. However, very few transplanted cell-derived, GFP-positive cells were found incorporated into the vascular structure, and GFP-positive cardiomyocytes were not detected in the repaired tissue. On the other hand, cultured CD34(+) cells were found to secrete vascular endothelial growth factor (VEGF), and the in vivo regional VEGF levels showed a significant increase after the transplantation. These results suggest that the improvement is not the result of generation of transplanted cell-derived endothelial cells or cardiomyocytes; and raise the possibility that angiogenic cytokines secreted from transplanted cells potentiate angiogenic activity of endogenous cells. 相似文献
63.
Endothelium-dependent vasodilation in type II diabetes mellitus 总被引:3,自引:0,他引:3
Furuta M Tsunoda K Arita M Nanjo K Sanke T 《Rinsho byori. The Japanese journal of clinical pathology》2003,51(11):1111-1115
Endothelial dysfunction is a major feature of atherosclerosis and it can also serve as an early atherosclerotic marker. Evaluation and assessment of the endothelial function is important to prevent serious atherosclerotic disease especially myocardial infarction, cerebrovascular disease and renal failure. To evaluate endothelial function we measured endothelium-dependent vasodilation (flow-mediated dilatation: %FMD) of the brachial artery with ultrasound. This method is non-invasive and can be repeatable in order to follow patients individually. Progressive atherosclerosis is often observed in diabetic patients who are not hypertensive. To evaluate the impairment of the endothelial function in type 2 diabetic patients, we examined %FMD in them and compared with hypertensive patients without diabetes and control subjects. We found that type 2 diabetic patients had the same endothelial dysfunction as hypertensive patients without diabetes. %FMD in both diabetic patients and hypertensive patients was lower than in control subjects. Moreover, %FMD of type 2 diabetic patients with hypertension was lower than %FMD of type 2 diabetic patients without hypertension. These finding suggests that endothelial dysfunction develops under the conditions of hypertension and hyperglycemia. Evaluating endothelial function with ultrasound is useful for assessment of atherosclerosis in diabetes. 相似文献
64.
Yasuyuki Shibuya Hisashi Yasuda Masaki Tomatsuri Akira Mizoguchi Masatoshi Takeichi Keikichi Shimada Chizuka Ide 《Journal of neurocytology》1996,25(1):615-624
Summary The Ca2+-dependent intercellular adhesion molecule cadherin is known to be linked to the cytoskeleton by the protein catenin, an association of which appears to be important for the cell-adhesion function of cadherin. Catenin consists of three subtypes-, , and . In our previous study, N-cadherin was shown to be localized on the plasmalemma of normal and regenerating chick peripheral nerve. Thus, as N-catenin is a subtype of -catenin (which is specifically associated with N-cadherin), we investigated the immunolocalization of N-catenin in normal and regenerating chick sciatic nerve. In normal nerve, unmyelinated axons exhibited either intense or weak N-catenin immunoreactivity throughout the axoplasm, whereas myelinated axons were completely immunonegative. Regenerating axons, including those derived from parent myelinated axons, showed N-catenin immunoreactivity of variable intensities in growth cones and axon shafts. Schwann cells were invariably devoid of immunoreactivity. Thus N-catenin is not necessarily bound to the surface plasmalemma, but is distributed throughout the cytoplasm, suggesting that most N-catenin molecules are dissociated from N-cadherin. 相似文献
65.
Yoshimitsu Inoue Mikio Nakao Syozo Okudaira Hiroyuki Ueda Tsutomu Araki 《European journal of applied physiology》1995,70(1):6-12
Eight older (60–65 years) and six younger (20–25 years) men were exposed to a standard heat stress for 60 min in summer, autumn, winter, and spring. The test consisted of placing the lower legs and feet in a 42°C water bath while sitting in constant environmental conditions (30°C and 45% relative humidity). The increase of rectal temperature (T
re) was significantly greater (P < 0.05) in autumn, winter, and spring than in summer for the older group, but significantly greater only in winter than in summer for the younger group (P < 0.05). The T
re was greater for the older group in all seasons, but of significance only in autumn and spring (P < 0.01). There were no significant season-related differences for metabolic heat production (m) and mean skin temperature (
sk) during the heat test in the respective groups, although the m and
sk were lower for the older group in all seasons (P < 0.01). In the older group total body sweating rate (msw) divided by T
re (total msw/T
re) decreased from summer to winter (P < 0.02) and did not differ between winter and spring, whereas total msw/T
re in the younger group increased in spring after decreasing from autumn to winter (P < 0.03). The variations of the value, local sweating rate on the back and thigh divided by T
re (back msw/T
re and thigh msw/T
re), were similar to those of the total msw/T
re in each group, except for back msw/T
re in the younger group, which did not increase from winter to spring. The total msw/T
re, back msw/T
re and thigh msw/T
re were significantly less for the older group in summer, autumn and spring (P < 0.05). The range of seasonal variations was significantly less for the older group (P < 0.001). The results indicated that, compared with younger men in older men, the enhancement of sweating function toward summer occurred later and its reduction toward winter occurred earlier despite a smaller range of seasonal variation and that older men had a somewhat lesser capability to maintainT
re when challenged by heat stress in all seasons. 相似文献
66.
H. Shimada K. Noda M. Mori N. Aoki M. Tajima K. Kato 《Virchows Archiv : an international journal of pathology》1994,424(5):569-572
Virions resembling papovavirus were demonstrated in glial cells in the brain of an aged patient without overt progressive multifocal leukoencephalopathy. The patient was not in a severely immunocompromised state. On histological examination, only a few tiny incomplete necrotic foci were found in the subcortical area. These foci were widely dispersed. Rare, swollen oligodendroglial cells and astrocytes in which papovavirus capsid protein (VP-1) was demonstrated immunohistochemically were present around the foci. The two typical types of virus particles i.e. 35 to 40 nm round particles and elongated particles, were observed in the nuclei of the swollen glial cells. The latter were in the minority. Distinct crystals were also found in the nuclei. The centre-to-centre distance of the particles in the crystals, about 40 nm, and the electron-opaque spots of the round-shaped virions and of the elongated particles, were indicative of structural subunits of papovavirus capsids. This case provides further evidence that papovavirus, possibly JC virus, may be reactivated in the brains of aged patients who are not in an immunocompromised state. 相似文献
67.
Specific-pathogen-free (SPF), 2-day-old chicks were inoculated with type A influenza virus (A/whistling swan/Shimane/499/83/(H5N3)) into their caudal thoracic air sac. The original isolate of the virus was of low virulence (ICPI 0. 20 to 0.40), and was passaged 10 times through the respiratory organs of SPF chicks. Most of the chicks inoculated with the passaged virus (strain 499) showed respiratory and alimentary signs. Three of 30 chicks died on days 2, 6 and 7 post-inoculation (p.i.). Almost half of the infected chicks showed poor growth, and the variation of body size in the flock became prominent from day 10 p.i. Infected chicks consistently had pathological changes in the pancreas, liver, kidneys and respiratory tracts, and occasionally in the brain, duodenum and bone marrow. Positive immunoreaction to avian influenza virus (AIV) antigen and recovery of the virus persisted for longer period in the pancreas than in other organs. The pancreatic lesions were caused by a direct, lytic virus infection of the acinar cells and contributed to poor growth of the chicks. 相似文献
68.
Effect of malnutritional rehabilitation on tuberculin reactivity and complement level in rats
下载免费PDF全文
![点击此处可从《Immunology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The purpose of this study was to clarify the effect of differing nutritional states on various components of the immune system, especially on the interplay of the complement system and cell-mediated immunity. Malnutrition was induced in Sprague—Dawley rats by feeding them diets containing 5% protein or 0.5% protein as compared with 18% protein in the diet of the controls. Nutritional rehabilitation was achieved in some experimental groups by transferring those fed 0.5% protein diet to the 18% protein diet. Malnutrition was confirmed by weight changes, biochemical findings in the sera, haematological observations and histological observation of the liver, and rehabilitation was confirmed by body weight increase and changes in other measurements. In rats suffering malnutrition, the tuberculin skin reactivity was suppressed. After feeding the 0.5% protein diet for 8 weeks, all the rats showed negative tuberculin skin reactions. In the malnourished rats, including those fed with 0.5% protein, the serum complement level decreased but did not show any significant differences as compared with the well nourished control group. After 1 week of nutritional rehabilitation, the tuberculin reactivity of six out of ten rats remained negative and after 2 weeks, all rats showed positive tuberculin reactions. After 1 week of nutritional rehabilitation, all the rats showed a normal or higher serum complement level. At this stage, two of the tuberculin-negative rats showed significantly higher titre of serum complement than even the controls. 相似文献
69.
Eiitsu Nakajima Hideo Orimo Miyoko Ikejima Takashi Shimada 《Journal of human genetics》1995,40(4):343-345
Summary We have identified a polymorphic 9-bp repeat sequence in exon 1 of thehMSH3 gene using polymerase chain reaction (PCR). Five alleles were observed in unrelated Japanese individuals with heterozygosity of 0.57. 相似文献
70.
Effect of serum amyloid P component level on transthyretin-derived amyloid deposition in a transgenic mouse model of familial amyloidotic polyneuropathy.
下载免费PDF全文
![点击此处可从《The American journal of pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
T. Murakami S. Yi S. Maeda F. Tashiro K. Yamamura K. Takahashi K. Shimada S. Araki 《The American journal of pathology》1992,141(2):451-456
To elucidate the pathogenesis of amyloid deposition associated with familial amyloidotic polyneuropathy (FAP), we developed several transgenic mouse lines carrying the human mutant transthyretin (TTR) gene. We found that human TTR and mouse serum amyloid P component (SAP) are deposited as amyloid in tissues of these mouse lines. Because SAP is a major acute-phase reactant in mice, we asked whether repeated injections of Escherichia coli lipopolysaccharide (LPS) would enhance the amyloid deposition in one of these transgenic mouse lines. During the course of repeated LPS injections, serum levels of SAP in the transgenic mice remained between severalfold to about 50-fold higher than seen in the absence of stimulation. As no significant difference was detected in the onset, progression, and tissue distribution of TTR-derived amyloid (ATTR) deposition between the LPS-stimulated and unstimulated transgenic mice, the induction of SAP synthesis by acute inflammation probably does not affect the onset and extent of ATTR deposition. 相似文献