全文获取类型
收费全文 | 12278篇 |
免费 | 565篇 |
国内免费 | 101篇 |
专业分类
耳鼻咽喉 | 90篇 |
儿科学 | 253篇 |
妇产科学 | 149篇 |
基础医学 | 1389篇 |
口腔科学 | 219篇 |
临床医学 | 697篇 |
内科学 | 3578篇 |
皮肤病学 | 353篇 |
神经病学 | 821篇 |
特种医学 | 368篇 |
外科学 | 1984篇 |
综合类 | 56篇 |
预防医学 | 358篇 |
眼科学 | 152篇 |
药学 | 623篇 |
中国医学 | 50篇 |
肿瘤学 | 1804篇 |
出版年
2023年 | 76篇 |
2022年 | 109篇 |
2021年 | 248篇 |
2020年 | 138篇 |
2019年 | 186篇 |
2018年 | 280篇 |
2017年 | 194篇 |
2016年 | 250篇 |
2015年 | 269篇 |
2014年 | 373篇 |
2013年 | 406篇 |
2012年 | 730篇 |
2011年 | 810篇 |
2010年 | 458篇 |
2009年 | 368篇 |
2008年 | 784篇 |
2007年 | 851篇 |
2006年 | 776篇 |
2005年 | 845篇 |
2004年 | 850篇 |
2003年 | 877篇 |
2002年 | 823篇 |
2001年 | 134篇 |
2000年 | 96篇 |
1999年 | 157篇 |
1998年 | 194篇 |
1997年 | 148篇 |
1996年 | 160篇 |
1995年 | 151篇 |
1994年 | 139篇 |
1993年 | 99篇 |
1992年 | 99篇 |
1991年 | 103篇 |
1990年 | 66篇 |
1989年 | 68篇 |
1988年 | 61篇 |
1987年 | 45篇 |
1986年 | 38篇 |
1985年 | 52篇 |
1984年 | 62篇 |
1983年 | 42篇 |
1982年 | 50篇 |
1981年 | 51篇 |
1980年 | 21篇 |
1979年 | 31篇 |
1978年 | 19篇 |
1977年 | 15篇 |
1975年 | 17篇 |
1974年 | 9篇 |
1973年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 897 毫秒
91.
Honma K Abraham JL Chiyotani K De Vuyst P Dumortier P Gibbs AR Green FH Hosoda Y Iwai K Williams WJ Kohyama N Ostiguy G Roggli VL Shida H Taguchi O Vallyathan V 《Human pathology》2004,35(12):1515-1523
We defined mixed-dust pneumoconiosis (MDP) pathologically as a pneumoconiosis showing dust macules or mixed-dust fibrotic nodules (MDF), with or without silicotic nodules (SN), in an individual with a history of exposure to mixed dust. We defined the latter arbitrarily as a mixture of crystalline silica and nonfibrous silicates. According to our definition of MDP, therefore, MDF should outnumber SN in the lung to make a pathologic diagnosis of MDP. In the absence of confirmation of exposure, mineralogic analyses can be used to support the pathologic diagnosis. The clinical diagnosis of MDP requires the exclusion of other well-defined pneumoconioses, including asbestosis, coal workers’ pneumoconiosis, silicosis, hematite miners’ pneumoconiosis, welders’ pneumoconiosis, berylliosis, hard metal disease, silicate pneumoconiosis, diatomaceous earth pneumoconiosis, carborundum pneumoconiosis, and corundum pneumoconiosis. Typical occupations associated with the diagnosis of MDP include metal miners, quarry workers, foundry workers, pottery and ceramics workers, and stonemasons. Irregular opacities are the major radiographic findings in MDP (ILO 1980), in contrast to silicosis, in which small rounded opacities predominate. Clinical symptoms of MDP are nonspecific. MDP must be distinguished from a variety of nonoccupational interstitial pulmonary disorders. 相似文献
92.
We evaluated human physiological responses and the performance of manual tasks during exposure to severe cold (–25°C) at
night (0300–0500 hours) and in the afternoon (1500–1700 hours). Thirteen male students wearing standard cold protective clothing
occupied a severely cold room (–25°C) for 20 min, and were then transferred to a cool room (10°C) for 20 min. This pattern
of exposure was repeated three times, for a total time of exposure to extreme cold of 60 min. The experiments were started
either at 1500 hours or 0300 hours and measurements of rectal temperature, skin temperature, blood pressure, performance in
a counting task, hand tremor, and subjective responses were made in each condition. At the end of the experiment at night
the mean decrease in rectal temperature [0.68 (SEM 0.04)°C] was significantly greater than that at the end of the experiment
in the afternoon [0.55 (SEM 0.08)°C, P<0.01]. After the second cold exposure at night the mean increase in diastolic blood pressure [90 (SEM 2.0) mmHg] was significantly
greater than that at the end of the second cold exposure in the afternoon [82 (SEM 2.8) mmHg, P<0.01]. At the end of the second cold exposure at night, mean finger skin temperature [11.8 (SEM 0.8)°C] was significantly
higher than that at the comparable time in the afternoon [9.0 (SEM 0.7)°C, P<0.01]. Similarly for the toe, mean skin temperature at the start of the second cold exposure at night [25.6 (SEM 1.5)°C]
was significantly higher than in the afternoon [20.1 (SEM 0.8)°C, P<0.01]. The increased skin temperatures in the periphery resulted in increased heat loss. Since peripheral skin temperatures
were highest at night, the subjects noted diminished sensations of thermal cold and pain at that time. Manual dexterity at
the end of the first cold exposure at night [mean 83.7 (SEM 3.6) times·min–1] had decreased significantly more than at the end of the first cold exposure in the afternoon [mean 89.4 (SEM 3.5) times·min–1, P<0.01]. These findings of a lowered rectal temperature and diminished manual dexterity suggest that there is an increased
risk of both hypothermia and accidents for those who work at night.
Electronic Publication 相似文献
93.
Helicobacter pylori does not require Lewis X or Lewis Y expression to colonize C3H/HeJ mice 下载免费PDF全文
Takata T El-Omar E Camorlinga M Thompson SA Minohara Y Ernst PB Blaser MJ 《Infection and immunity》2002,70(6):3073-3079
Helicobacter pylori strains frequently express Lewis X (Le(x)) and/or Le(y) on their cell surfaces as constituents of the O antigens of their lipopolysaccharide molecules. To assess the effect of Le(x) and Le(y) expression on the ability of H. pylori to colonize the mouse stomach and to adhere to epithelial cells, isogenic mutants were created in which fucT1 alone or fucT1 and fucT2, which encode the fucosyl transferases necessary for Le(x) and Le(y) expression, were deleted. C3H/HeJ mice were experimentally challenged with either wild-type 26695 H. pylori or its isogenic mutants. All strains, whether passaged in the laboratory or recovered after mouse passage, colonized the mice well and without consistent differences. During colonization by the mutants, there was no reversion to wild type. Similarly, adherence to AGS and KatoIII cells was unaffected by the mutations. Together, these findings indicate that Le expression is not necessary for mouse gastric colonization or for H. pylori adherence to epithelial cells. 相似文献
94.
Shigehito Yamada Chigako Uwabe Tomoko Nakatsu-Komatsu Yutaka Minekura Masaji Iwakura Tamaki Motoki Kazuhiko Nishimiya Masaaki Iiyama Koh Kakusho Michihiko Minoh Shinobu Mizuta Tetsuya Matsuda Yoshimasa Matsuda Tomoyuki Haishi Katsumi Kose Shingo Fujii Kohei Shiota 《Developmental dynamics》2006,235(2):468-477
Morphogenesis in the developing embryo takes place in three dimensions, and in addition, the dimension of time is another important factor in development. Therefore, the presentation of sequential morphological changes occurring in the embryo (4D visualization) is essential for understanding the complex morphogenetic events and the underlying mechanisms. Until recently, 3D visualization of embryonic structures was possible only by reconstruction from serial histological sections, which was tedious and time-consuming. During the past two decades, 3D imaging techniques have made significant advances thanks to the progress in imaging and computer technologies, computer graphics, and other related techniques. Such novel tools have enabled precise visualization of the 3D topology of embryonic structures and to demonstrate spatiotemporal 4D sequences of organogenesis. Here, we describe a project in which staged human embryos are imaged by the magnetic resonance (MR) microscope, and 3D images of embryos and their organs at each developmental stage were reconstructed based on the MR data, with the aid of computer graphics techniques. On the basis of the 3D models of staged human embryos, we constructed a data set of 3D images of human embryos and made movies to illustrate the sequential process of human morphogenesis. Furthermore, a computer-based self-learning program of human embryology is being developed for educational purposes, using the photographs, histological sections, MR images, and 3D models of staged human embryos. 相似文献
95.
Mitsuyo Nishimura Tetsuro Kodama Hiroyuki Nishiyama Yutaka Nishiwaki Tomoyuki Yokose Yukio Shimosato 《Pathology international》1997,47(4):260-263
A 57-year-old woman presented with a 10×10 cm anterior mediations mass. The tumor had Invaded the pericardium, both lungs and the left brachiocephallc vein, and was treated by partial resection and postoperative radiation therapy. Pathological examination of the tumor revealed squamous cell carcinoma with a spindle cell sarcomatous component. Immunohistochemically, keratin and epithelial membrane antlgen were posltive In both the spindle cell sarcomatous areas and the squamous cell carcinomatous area and thus, a diagnosis of thymic carcinoma of sarcomatoid type was made. The patient died of recurrent disease 1 year after surgery. This case is the seventh reported In the English literature Because of the poor outcome, adjuvant therapy is recommended. 相似文献
96.
Masafumi Hara Yutaka Tsutsumi 《Virchows Archiv : an international journal of pathology》1986,408(4):385-394
Summary Twenty-one specimens of heterotopic pancreas were investigated using the indirect immunoperoxidase method for insulin, somatostatin, glucagon, pancreatic polypeptide (PP) and gastrin. Ten specimens showed ducts, acini and islets, seven showed ducts and acini, and four showed a ductal component alone. Pyloric gland-like mucous glands were occasionally identified in association with the ductal component. In eight of ten lesions containing islets, the islets were round and had a clearly defined outline with many glucagon cells and either none or a modest number of PP cells (dorsal type). In the remaining two lesions, the islets showed varying sizes and irregular outline with many PP cells and a few or no glucagon cells (ventral type). In either type of islets, insulin and somatostatin were detected, but gastrin cells were absent. Some isolated endocrine cells were also present among the acinar and ductal components. Their occurrence in ducts was more frequent in lesions or areas mainly composed of the ductal compoment than in those with less prominent ductal tissue. In eight lesions a few gastrin cells were found in the ductal component which showed goblet cell metaplasia and pyloric gland metaplasia. An intimate relationship between goblet cell metaplasia and appearance of G cells is noteworthy. 相似文献
97.
Unlike acetylcholine, caffeine was much more effective in releasing catecholamine in the absence of extracellular Ca2+ than in its presence in perfused cat adrenal glands. The intracellular Ca2+ antagonist, TMB-8 (10−4 M), inhibited reversibly the catecholamine secretion evoked by caffeine (40 mM) and that induced by acetylcholine (10−4 M) in the presence of hexamethonium (10−3 M) during perfusion with Ca2+-free Locke solution containing EGTA (10−5 M). These results support our view that muscarinic receptor activation causes catecholamine secretion by mobilizing Ca2+ from an intracellular pool just as caffeine does. 相似文献
98.
Koga T Hashimoto S Sugio K Yonemitsu Y Nakashima Y Yoshino I Matsuo Y Mojtahedzadeh S Sugimachi K Sueishi K 《American journal of clinical pathology》2002,117(3):464-470
We assessed the occurrence of atypical adenomatous hyperplasia (AAH) in whole lung lobes with primary cancer lesions. Following surgical resection, tissue specimens were sliced to a thickness of 4 mm (3,641 specimens from 61 cases; mean = 59.7 specimens per case). A total of 119 AAH foci were found and an association was evident in 25 (57%) of 44 adenocarcinomas, 3 (30%) of 10 squamous cell carcinomas, and 2 (29%) of 7 other lung cancers. Histologic evaluation showed that 108 AAH foci were categorized as low-grade and the other 11 as high-grade AAH. These 11 foci of high-grade AAH were present in 7 patients with adenocarcinoma, and in 1 patient there was a synchronous double primary lung adenocarcinoma. High-grade AAH was closely associated with bronchioloalveolar carcinoma (BAC) type adenocarcinoma, and low-grade AAH with non-BAC adenocarcinoma. The mean +/- SD Ki-67 labeling index in high-grade AAH (3.5%+/-2.9%) was significantly higher than for the low-grade index (1.4%+/-1.6%). We propose that foci of high- but not low-grade AAH may be potential precursor lesions of lung adenocarcinoma, especially with the BAC component. 相似文献
99.
100.
Takashi Sekine Keiko Fukutani Tomiko Motegi Hiroshi Hayakawa Takashi Tamura Shigeo Nagafuchi Yutaka Nakahori Yasuo Nakagome 《Journal of human genetics》1992,37(2):157-162
Summary Results of DNA study on two patients of gonadal dysgenesis with a 45,X/46,X,Ynf (non-fluorescent Y chromosome) karyotype are described. In one patient who developed gonadoblastoma, all 12 loci on the non-fluorescent part of Yq were detected. Another patient did not have gonadoblastoma at 20 years, and only the proximal 6 loci out of 12 were detected. 相似文献