全文获取类型
收费全文 | 12439篇 |
免费 | 627篇 |
国内免费 | 99篇 |
专业分类
耳鼻咽喉 | 64篇 |
儿科学 | 187篇 |
妇产科学 | 193篇 |
基础医学 | 1534篇 |
口腔科学 | 155篇 |
临床医学 | 752篇 |
内科学 | 3664篇 |
皮肤病学 | 223篇 |
神经病学 | 814篇 |
特种医学 | 596篇 |
外科学 | 2321篇 |
综合类 | 82篇 |
预防医学 | 215篇 |
眼科学 | 121篇 |
药学 | 835篇 |
4篇 | |
中国医学 | 42篇 |
肿瘤学 | 1363篇 |
出版年
2024年 | 20篇 |
2023年 | 90篇 |
2022年 | 159篇 |
2021年 | 334篇 |
2020年 | 166篇 |
2019年 | 212篇 |
2018年 | 275篇 |
2017年 | 230篇 |
2016年 | 298篇 |
2015年 | 318篇 |
2014年 | 388篇 |
2013年 | 434篇 |
2012年 | 769篇 |
2011年 | 870篇 |
2010年 | 453篇 |
2009年 | 437篇 |
2008年 | 746篇 |
2007年 | 911篇 |
2006年 | 839篇 |
2005年 | 856篇 |
2004年 | 843篇 |
2003年 | 855篇 |
2002年 | 788篇 |
2001年 | 152篇 |
2000年 | 102篇 |
1999年 | 156篇 |
1998年 | 209篇 |
1997年 | 181篇 |
1996年 | 148篇 |
1995年 | 143篇 |
1994年 | 98篇 |
1993年 | 119篇 |
1992年 | 80篇 |
1991年 | 61篇 |
1990年 | 71篇 |
1989年 | 50篇 |
1988年 | 45篇 |
1987年 | 41篇 |
1986年 | 29篇 |
1985年 | 19篇 |
1984年 | 20篇 |
1983年 | 22篇 |
1982年 | 18篇 |
1981年 | 11篇 |
1980年 | 17篇 |
1979年 | 10篇 |
1978年 | 12篇 |
1977年 | 8篇 |
1975年 | 7篇 |
1974年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 296 毫秒
81.
Shigesaburo Miyakoshi Eiji Kusumi Tomoko Matsumura Akiko Hori Naoko Murashige Tamae Hamaki Koichiro Yuji Naoyuki Uchida Kazuhiro Masuoka Atsushi Wake Yoshinobu Kanda Masahiro Kami Yuji Tanaka Shuichi Taniguchi 《Biology of blood and marrow transplantation》2007,13(7):771-777
Invasive fungal infection (IFI) is a significant complication after allogeneic hematopoietic stem cell transplantation (HSCT); however, we have little information on its clinical features after reduced intensity cord blood transplantation (RICBT) for adults. We reviewed medical records of 128 patients who underwent RICBT at Toranomon Hospital between March 2002 and November 2005. Most of the patients received purine-analogbased preparative regimens. Graft-versus-host disease (GVHD) prophylaxis was a continuous infusion of either tacrolimus 0.03 mg/kg or cyclosporine 3 mg/kg. IFI was diagnosed according to the established EORTC/NIH-MSG criteria. IFI was diagnosed in 14 patients. Thirteen of the 14 had probable invasive pulmonary aspergillosis and the other had fungemia resulting from Trichosporon spp. Median onset of IFI was day 20 (range: 1-82), and no patients developed IFI after day 100. Three-year cumulative incidence of IA was 10.2%. Four of the 13 patients with invasive aspergillosis (IA) developed grade II-IV acute GVHD, and their IA was diagnosed before the onset of acute GVHD. The mortality rate of IFI was 86%. Multivariate analysis revealed that the use of prednisolone >0.2 mg/kg (relative risk 7.97, 95% confidence interval 2.24-28.4, P = .0014) was a significant risk factor for IA. This study suggests that IFI is an important cause of deaths after RICBT, and effective strategies are warranted to prevent IFI. 相似文献
82.
The hippocampal formation contains a variety of neuronal types. The principal neurons are granule cells in the dentate gyrus and pyramidal cells in Ammon's horn. These two neuron types show distinct cell morphology and display a different vulnerability to ischemic injury or various neurotoxins. In order to illustrate the difference in the pathophysiological properties of these neurons, we established a method for separately culturing granule cells and pyramidal cells. They were prepared from the dentate gyrus and Ammon's horn of 3-day-old Wistar rat pups and maintained for 7–9 days in culture. After transient exposure to N-methyl-D-aspartate or glutamate, both the cultured neuron populations displayed somatic Ca2+ transients with similar amplitudes, but the subsequent recovery to baseline was about twice as fast in granule cells than in pyramidal cells. Similar results were obtained for K+ depolarization-induced Ca2+ elevation, suggesting that the relatively rapid Ca2+ clearance in granule cells is independent of Ca2+ influx pathways. The present study provides the first evidence for a difference in Ca2+ dynamics and homeostasis between granule and pyramidal cells and may represent a cellular basis for the differential vulnerability of hippocampal neurons. 相似文献
83.
Hirokazu Taniguchi Kenjiro Hamamoto Takahiro Nagano Yuji Kishimoto Takashi Kimura Hideki Fujitake Kojiro Yasunaga 《Medical Electron Microscopy》1993,26(1):13-18
Ultrastructural myeloperoxidase (MPO) activity and myeloid-associated antigen (MyAg) expression were investigated in 12 adult
patients with acute lymphoblastic leukemia (ALL). Ultrastructural MPO was detected by 3 different methods. Immunophenotyping
was performed by flow cytometry, using a series of monoclonal antibodies. Ultrastructural MPO-positive blast cells were detected
in 6 patients (50%). In 5 of these 6 patients, the methods detecting both MPO and platelet peroxidase (PPO) activities found
MPO-positive blast cells more frequently than those detecting MPO activity alone. In 2 patients (17%), at least one kind of
MyAg was positive. Ultrastructural MPO activity was detected more frequently than MyAg expression in ALL patients. This method
of detecting PPO and MPO is recommended for detection of ultrastructural MPO-positive ALL. 相似文献
84.
Nuclear accumulation of beta-catenin in intestinal-type gastric carcinoma: correlation with early tumor invasion 总被引:4,自引:0,他引:4
Miyazawa K Iwaya K Kuroda M Harada M Serizawa H Koyanagi Y Sato Y Mizokami Y Matsuoka T Mukai K 《Virchows Archiv : an international journal of pathology》2000,437(5):508-513
Mutation of the adenomatous polyposis coli gene, which is known to be an early event in the carcinogenesis of intestinal-type gastric carcinoma, leads to accumulation of beta-catenin. In addition, beta-catenin has been found to activate down stream signaling molecules in the wingless/Wnt pathway. In this study, the clinical significance of nuclear accumulation of beta-catenin was evaluated in gastric carcinoma. Immunohistochemical staining showed nuclear localization in 16 (12%) of 139 (94 intestinal-type and 45 diffuse-type) gastric carcinomas, and all 16 lesions with nuclear staining were intestinal-type adenocarcinomas. Of the 16 cases, 15 were in the early clinical stage. In the remaining case, the lesion had invaded the subserosal layer and showed strong nuclear staining at the invasive front. In 14 of the 16 cases with nuclear localization, there were no abnormal mobility shifts detected using polymerase chain reaction-single strand conformational polymorphism analysis. This was confirmed using direct sequencing analysis, which revealed the wild-type sequence in the 12 cases tested. Nuclear accumulation of beta-catenin did not correlate with lymph node metastasis or 5-year survival. These findings suggest that high intranuclear levels of beta-catenin protein play an important role in early tumor growth and may function in initiation of invasive processes in intestinal-type gastric carcinoma. 相似文献
85.
Yuji Ohtsuki Bruce Mackay Jae Y. Ro Alberto G. Ayala 《Medical Electron Microscopy》1998,31(4):222-225
We report ribosome-lamella complexes (RLC) in cancer cells of transitional cell carcinoma (TCC) of the prostate in a 52-year-old Caucasian man. Histopathologically, cancer cells were proliferated in various-sized nests, mostly associated with central necrosis. Some invaded into the surrounding normal glandular space and the stroma, with occasional lymphatic invasion. Fine structural study of cancer cells revealed that cross-sectioned RLC as well as densely aggregated ribosomes were detected in their cytoplasm, situated close to, but not directly connected with, dilated rough endoplasmic reticulum. These were composed of a concentric alternative arrangement of both lamellae and ribosomes. In the central and surrounding parts of the RLC, ribosomes were observed, revealing a smooth transition to the ribosomal component of RLC in size and shape. The presence of both RLC and dense aggregation of ribosomes close to the rough endoplasmic reticulum suggests that their functions might be related to specific or aberrant protein synthesis under unknown conditions. Although RLC have been often reported in hematopoietic malignancies, their occurrence in the malignant epithelial component has been only reported in a case of pulmonary adenocarcinoma. This is the first report of RLC in TCC in the literature. 相似文献
86.
Kashimura T Kodama M Hotta Y Hosoya J Yoshida K Ozawa T Watanabe R Okura Y Kato K Hanawa H Kuwano R Aizawa Y 《Virchows Archiv : an international journal of pathology》2004,444(3):283-292
Coxsackievirus B is the most common cause of viral myocarditis and is particularly virulent in neonates and children. Adenovirus is also a leading cause of the disease. The determinant of tropism for both viruses is considered to be the expression of coxsackievirus and adenovirus receptor (CAR) in target organs. However, developmental change and physiological localization of CAR in the heart are unknown. We examined expression levels of CAR in rat hearts by quantitative real-time polymerase chain reaction and Western blot analysis and found that CAR decreased gradually during postnatal development, although CAR was detectable, even in adults. Immunohistochemistry revealed CAR on the whole surface of cardiomyocytes in immature rat hearts. In contrast, CAR was detected predominantly on intercalated disks in the adult heart and was accumulated especially at the contact point between the cultured cardiomyocytes, even though they were prepared from the neonatal rat heart. In conclusion, CAR was expressed abundantly on the whole surface of cardiomyocytes in immature rat hearts. Both the expression level and the localization of CAR are possible determinants of the susceptibility to viral myocarditis of neonates and children. 相似文献
87.
88.
Ivan Kocic Yuji Hirano Masayasu Hiraoka 《Pflügers Archiv : European journal of physiology》2002,443(3):353-361
Hamsters are frequently studied as a model of cardiomyopathy, but the electrophysiological properties of a hamster heart are not well defined. We examined rate-dependent changes in action potentials and underlying ionic mechanisms in isolated ventricular myocytes from hamster hearts using the whole-cell configuration of the patch clamp technique. At 0.1 Hz stimulation, the mean action potential duration at 90% (APD90) and 20% (APD20) repolarization were 63+/-7 ms and 9+/-1 ms, respectively ( n=17). With increasing frequency of stimulation, APD progressively prolonged to 119+/-16 ms (APD90) and 36+/-7 ms (APD20) at 6.0 Hz. A further increase in the rate of stimulation to 8.0 Hz did not change APD significantly. Application of 4 mM 4-aminopyridine (4-AP) lengthened APD markedly and completely prevented the rate-dependent prolongation. Cd2+ (0.2 mM) shortened APD and generally attenuated the rate-dependent lengthening of APD up to 5.0 Hz, but unaffected the lengthening of APD with the further increase in the rate. At plateau voltages, there were two time-dependent currents, Ito1 and I(Ca,L). Recovery from inactivation for Ito1 had two components: t(slow)=980+/-129 ms accounting for 58% of the total fraction, and t(fast)=39+/-13 ms ( n=7). Recovery from inactivation for I(Ca,L) was rapid with t=20+/-4 ms ( n=6). Results suggest that the slow recovery from inactivation in Ito1 is the main reason for the rate-dependent prolongation of APD in hamster ventricular myocytes. 相似文献
89.
90.
Kobayashi M Masuda Y Fujimoto Y Matsuya T Yamamura K Yamada Y Maeda N Morimoto T 《Physiology & behavior》2002,75(3):377-385
Although rhythmic jaw movement in feeding has been studied in mammals, such as rats, rabbits and monkeys, the cellular and molecular mechanisms underlying it are not well understood. Transgenic and gene-targeting technologies enable direct control of the genetic makeup of the mouse, and have led to the development of a new category of reagents that have the potential to elucidate the cellular and molecular mechanisms of neural networks. The present study attempts to characterize rhythmic jaw movements in the mouse and to demonstrate its relevance to rhythmic jaw movements found in higher mammals using newly developed jaw-tracking systems and electromyograms of the masticatory muscles. The masticatory sequence of the mouse during feeding was classified into two stages, incision and chewing. Small and rapid (8 Hz) open-close jaw movements were observed during incision, while large and slow (5 Hz) open-close jaw movements were observed during chewing. Integrated electromyograms of the masseteric and digastric muscles were larger during chewing than those observed during incision. Licking behavior was associated with regular (8 Hz), small open-close jaw movements with smaller masseteric activity than those observed during mastication. Grooming showed variable patterns of jaw movement and electromyograms depending on the grooming site. These results suggest that there are neuronal mechanisms producing different frequencies of rhythmic jaw movements in the mouse, and we conclude that the mouse is useful for understanding rhythmic jaw movements in higher mammals. 相似文献