全文获取类型
收费全文 | 21332篇 |
免费 | 1095篇 |
国内免费 | 151篇 |
专业分类
耳鼻咽喉 | 223篇 |
儿科学 | 479篇 |
妇产科学 | 206篇 |
基础医学 | 2365篇 |
口腔科学 | 375篇 |
临床医学 | 1489篇 |
内科学 | 5959篇 |
皮肤病学 | 455篇 |
神经病学 | 1603篇 |
特种医学 | 813篇 |
外科学 | 3980篇 |
综合类 | 51篇 |
预防医学 | 498篇 |
眼科学 | 400篇 |
药学 | 1147篇 |
中国医学 | 49篇 |
肿瘤学 | 2486篇 |
出版年
2024年 | 31篇 |
2023年 | 197篇 |
2022年 | 393篇 |
2021年 | 691篇 |
2020年 | 373篇 |
2019年 | 468篇 |
2018年 | 626篇 |
2017年 | 413篇 |
2016年 | 575篇 |
2015年 | 544篇 |
2014年 | 763篇 |
2013年 | 872篇 |
2012年 | 1398篇 |
2011年 | 1638篇 |
2010年 | 907篇 |
2009年 | 807篇 |
2008年 | 1331篇 |
2007年 | 1377篇 |
2006年 | 1344篇 |
2005年 | 1396篇 |
2004年 | 1439篇 |
2003年 | 1294篇 |
2002年 | 1190篇 |
2001年 | 213篇 |
2000年 | 195篇 |
1999年 | 218篇 |
1998年 | 251篇 |
1997年 | 230篇 |
1996年 | 162篇 |
1995年 | 148篇 |
1994年 | 148篇 |
1993年 | 114篇 |
1992年 | 114篇 |
1991年 | 108篇 |
1990年 | 77篇 |
1989年 | 62篇 |
1988年 | 53篇 |
1987年 | 54篇 |
1986年 | 48篇 |
1985年 | 37篇 |
1984年 | 49篇 |
1983年 | 29篇 |
1982年 | 26篇 |
1981年 | 22篇 |
1980年 | 19篇 |
1979年 | 23篇 |
1977年 | 13篇 |
1976年 | 13篇 |
1975年 | 13篇 |
1973年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
101.
Satoshi Yamagiwa Yuh Kuwano Katsuhiko Hasegawa Kazunari Sato Kazuo Ohtsuka Tsuneo Iiai Katsuhiro Tomiyama Hisami Watanabe Satoshi Sugahara Shuhji Seki Hitoshi Asakura Toru Abo 《European journal of immunology》1996,26(7):1409-1416
Mice carrying the lpr gene, SCG and MRL-lpr/lpr mice, were used to characterize the phenotype and lpr gene of abnormally proliferating T cells in these mice. A major population which expanded in these mice were T cells expressing intermediate (int) levels of T cell receptor (TCR) (and CD3) and the phenotype of interleukin-2 receptor (IL-2R)βlo α? (possibly abnormal TCRint cells). The levels of TCRhi cells of thymic origin (generated through the mainstream of T cell differentiation in the thymus) profoundly decreased after the onset of disease. However, a small population of normal TCRint cells (i.e. IL-2Rβhi α?) were also found to exist in all tested organs. For example, the majority of abnormal IL-2Rβlo TCRint cells were CD4?8? CD2?, while normal IL-2Rβhi TCRint cells were a mixture of single-positive cells (mainly CD8+), CD4?8? cells and CD2+ cells. Moreover, normal TCRint cells preferentially produced normal Fas mRNA and Fas molecules from the lpr gene. This phenomenon explains the leaky appearance of normal Fas mRNA and Fas molecules in mice carrying the lpr gene. It is suggested that a small population of IL-2RβhiTCRint cells are resistant to the lpr genetic abnormality. 相似文献
102.
Immunohistochemical characteristics of duodenal adenomas in familial adenomatous polyposis with special reference to cell kinetics 总被引:4,自引:0,他引:4
The duodenum is the second most frequent site of cancer in patients with familial adenomatous polyposis (FAP). The main objective of this study was to evaluate the cell kinetics in duodenal and ampullary adenomas in FAP. The endoscopic and biopsy findings of duodenal adenomas in 22 FAP subjects and 18 non-FAP subjects were compared. Adenomas in FAP included 15 ampullary adenomas and 17 nonampullary adenomas. The cell kinetics was evaluated by immunohistochemistry for Ki-67, p53, bcl-2, and cyclooxygenase 2 (COX2), and the apoptotic index (AI) as determined by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling (TUNEL) method. Any correlations between the indices for cell kinetics and the endoscopic findings were identified. All 50 adenomas were histologically verified to be tubular adenoma with low-grade dysplasia. Neither the expression of Ki-67, p53, bcl-2, and COX2 nor the AI differed substantially between FAP and non-FAP subjects. In patients with FAP, duodenal adenoma tended to have a higher Ki-67-labeling index than the ampullary adenoma (54.3 +/- 11.3 versus 46.8 +/- 12.7; .05 < P < .1). In addition, the Ki-67-labeling index in endoscopically normal or slightly enlarged ampullary adenoma was significantly higher than that in markedly enlarged ampullary adenoma (51.8 +/- 11.4 versus 39.4 +/- 11.3; P < .05). Duodenal adenoma in FAP subjects was not found to have a higher proliferative activity or a smaller degree of apoptosis compared with those in non-FAP subjects. The smaller proliferative activity in larger ampullary adenoma may thus be related to the static nature of ampullary adenoma in FAP. 相似文献
103.
Generators of visual evoked potentials for faces and eyes in the human brain as determined by dipole localization 总被引:4,自引:0,他引:4
Human visual evoked potentials were recorded during presentation of photos of human and animal faces and various face features. Negative waves with approximate peak latencies of 165 msec (N170) were bilaterally recorded from the occipito-temporal regions. Mean peak latencies of the N170 were shorter for faces than eyes only. Analyses of amplitudes of evoked potentials indicated that the N170 elicited by faces reflected activity of a specific neural system which was insensitive to detailed differences among individual faces regardless of species, and consequently suggest that this system might function to detect existence of faces in general. On the other hand, the mean amplitude of the N170 elicited by human eyes was significantly larger than those by animal eyes. These differences in response latencies and amplitudes of the N170 suggest existence of at least 2 different visual evoked potentials with similar latencies (i.e., N170) which are sensitive to faces in general and human eyes, respectively. Dipole source localization analysis indicated that dipoles for the N170 elicited by eyes were located in the posterior inferior temporal gyrus, and those for faces, located initially in the same region, but moved toward the fusiform and lingual gyri at the late phase of the N170. The results indicated that information processing of faces and eyes separated at least as early as the latency of the N170 at the posterior inferior temporal gyrus as well as the fusiform and lingual gyri, and might provide neurophysiological and anatomical bases to an initial structural encoding stage of human faces. 相似文献
104.
BACKGROUND: Japanese cedar pollinosis (JCP) affects more than 16% of the Japanese population. The estimated direct and indirect costs for this disease totaled 286 billion yen in 1998. In JCP therapy, antihistamines are first line agents. It is well known that starting treatment for JCP with antihistamines before initial day of the pollen scattering can relieve nasal symptom severity during pollen season. The aim of this study is to assess the clinical efficacy and cost-quality of 7 major second-generation antihistamines in early treatment for Japanese cedar pollinosis (JCP). METHODS: Patients were randomly selected from 16 ENT clinical sites in Osaka and Wakayama between February 24 and March 8, 2003 (peak pollen season). Effectiveness was assessed using patient'ratings of nasal and ocular symptoms and overall assessment in their condition compared to previous season ones. Costs include direct costs of the drugs used for treatment to JCP from January to March. RESULTS: One hundred seventy-five patients who were treated with antihistamine monotherapy (azelastine: n=15, cetirizine: n=15, ebastine: n=36, epinastine: n=16, fexofenadine: n=16, loratadine: n=60, oxatomide: n=17) and 510 non-treatment patients were evaluated. Among 8 groups, there were significant differences in sneezing, rhinorrhea, ocular itching and overall health condition. However, among 7 monotherapy groups, there were no differences in each symptom or the overall assessment. In cost-quality analysis, there were significant differences in a cost for each effective patient (defined as those with improvement in their overall condition) among 7 drugs. The top three cost-efficacious drugs resulted in azelastine, loratadine and fexofenadine. CONCLUSION: These results show that there were no significant differences in clinical efficacy in early treatment for JCP among 7 antihistamines. But Japanese National Health Insurance drug price scheme led to significant differences in cost-quality. 相似文献
105.
Satoshi Ishikawa Koji Ishizu Takashi Fukutomi 《Macromolecular chemistry and physics.》1991,192(5):1177-1181
The method formerly used to determine the crystallite core size of polyethylene was applied to poly(tetrahydrofuran) (PTHF). This method is based on the different diffusivity of a chaincleaving agent in crystalline and amorphous parts of the polymer. Butyllithium was used as a cleaving agent of PTHF. The degree of polymerization of the undecomposed part of the polymer (PTHF crystallites) was determined by gel permeation chromatography. This value agrees well with the value to be expected from the size of the crystallites determined small-angle X-ray scattering. 相似文献
106.
To clarify the relationship between macrophages and development of glomerulosclerosis, the authors developed a new experimental nephritis model with macrophages persisting in Thy-1 nephritis. Methyl-cellulose was administered intraperitoneally in addition to the intravenous injection of the anti-Thy-1 antibody to Wistar rats. Foamy macrophages influxed into the lytic mesangium and stayed to form nodular aggregates. Mesangial cells proliferated with the formation of extracellular matrices around these nodular aggregates of macrophages. Immunohistochemical analyses revealed that alpha-smooth muscle actin (alpha-SMA) was expressed in the proliferative area around these nodules of foamy macrophages from day 7. Type I collagen and type IV collagen were also expressed around the foamy macrophages in correspondence with alpha-SMA expression from day 7. The electron microscopic study revealed that collagen fibrils were formed around the transformed mesangial cells. The expression of platelet endothelial cell adhesion molecule-1 (PECAM-1, CD31), a marker of glomerular vasculature endothelial cells, was not found in the area occupied by the foamy macrophages, suggesting the impairment of glomerular reconstruction. Macrophages may participate in the progression of glomerulosclerosis in Thy-1 nephritis by enhancing the production of the extracellular matrix through transformed mesangial cells and preventing reconstruction of the capillary network. 相似文献
107.
Satoshi Kojima Hiroshi Nanakamura Shin Nagayama Yutaka Fujito Etsuro Ito 《Neuroscience letters》1997,230(3):517-182
To study the neuronal mechanism of a conditioned taste-aversion (CTA) learning in the pond snail Lymnaea stagnalis, we examined the synaptic connection between the neuron 1 medial (N1M) cell and the cerebral giant cell (CGC), the former is an interneuron in central pattern generator for the feeding response and the latter is a regulatory neuron to the central pattern generator. Inhibitory postsynaptic potential (IPSP) which was evoked in the N1M cell by activation of the CGC was larger and lasted longer in the conditioned animal than that in the control animal. The electrical properties of the cell body of CGC and the responses of the CGC to the chemosensory inputs were not changed during the CTA learning. These results, together with the previous report indicating the existence of excitatory projection from the N1M cell to the feeding motoneuron, suggest that enhanced IPSP in the N1M cell may underlie the suppression of feeding responses in the Lymnaea CTA learning. 相似文献
108.
Cerebral Processing of Acute Skin and Muscle Pain in Humans 总被引:12,自引:0,他引:12
109.
Jojiro Jakada Nozomu Furuta Motoshi Kawahara Shoichi Onodera Yukihiko Oishi Masaaki Kawada Tomolcazu Matsuura Satoshi Hasumura Seishi Nagamori 《Medical Electron Microscopy》1998,31(1):24-30
Primary cell cultures of two human pheochromocytomas (PC) that were associated with high serum levels of adrenaline and noradrenaline were developed to study the effects of nerve growth factor (NGF) and dexamethasone on the morphology and function of PC cells in vitro. By phase-contrast microscopy, cultured cells were small and hyperchromatic on the first day of culture; neurite-like processes that extended to other cells developed several days later and were maintained for more than 3 months. NGF (100ng/ml), dexamethasone (10–5M), or NGF + dexamethasone were added to the culture media 2 weeks after the cultured cells had stabilized. Catecholamine concentrations in the medium were maintained at higher levels after addition of NGF, dexamethasone, or NGF + dexamethasone as compared to control cells. In the presence of NGF, extension of neurite-like processes was clearly accelerated, while high levels of dexamethasone inhibited growth of processes. These in vitro studies showed that the addition of NGF or the removal of dexamethasone induces differentiation of adrenal neurons present in pheochromocytomas, suggesting that adrenocortical steroid hormones influence the morphological control of adrenal medullary cells. 相似文献
110.
Satoshi Fujishita Noritoshi Shibuya Norio Niikawa Shigenobu Nagataki 《Journal of human genetics》1991,36(4):317-324
Polymerase chain reaction (PCR)-based diagnosis was carried out in 62 patients (57 probands) with Duchenne or Becker muscular dystrophy (DMD or BMD) and 226 members in 57 families. The PCR studies were also performed for carrier detection in 57 mothers and 58 sisters, and prenatal diagnosis of 4 fetuses at risk of DMD. The PCR with 7 sets of primers, which amplify 7 different exon-sequences of the dystrophin gene, detected gene deletion of at least one exon in 49% of the probands. The PCR with the other 4 primer sets, which amplify 3 intragenic loci, and subsequent endonuclease digestion detected in 84% of the mothers a heterozygous pattern in at least one such locus/segment. Using the same primer sets, carrier detection was successful in 5 sisters of familial DMD cases, while recombination between the ERT87 and the 3 end intragenic loci was observed in 11% of family members studied. Prenatal diagnosis was made in all the 4 fetuses; two males were affected, one male fetus non-affected, and the remaining one female fetus a carrier. Thus, the PCR study and the primers used in the present study are useful and convincing for rapid diagnosis of DMD and/or BMD. 相似文献