全文获取类型
收费全文 | 705743篇 |
免费 | 48868篇 |
国内免费 | 1304篇 |
专业分类
耳鼻咽喉 | 9166篇 |
儿科学 | 23267篇 |
妇产科学 | 17603篇 |
基础医学 | 110382篇 |
口腔科学 | 19955篇 |
临床医学 | 63748篇 |
内科学 | 134287篇 |
皮肤病学 | 16160篇 |
神经病学 | 49428篇 |
特种医学 | 25737篇 |
外国民族医学 | 76篇 |
外科学 | 104459篇 |
综合类 | 14818篇 |
现状与发展 | 2篇 |
一般理论 | 160篇 |
预防医学 | 51384篇 |
眼科学 | 16318篇 |
药学 | 53941篇 |
3篇 | |
中国医学 | 2359篇 |
肿瘤学 | 42662篇 |
出版年
2019年 | 5430篇 |
2018年 | 7857篇 |
2017年 | 6104篇 |
2016年 | 6818篇 |
2015年 | 7548篇 |
2014年 | 10260篇 |
2013年 | 15376篇 |
2012年 | 20487篇 |
2011年 | 21481篇 |
2010年 | 12715篇 |
2009年 | 11928篇 |
2008年 | 19983篇 |
2007年 | 21502篇 |
2006年 | 21894篇 |
2005年 | 20432篇 |
2004年 | 19982篇 |
2003年 | 18937篇 |
2002年 | 18448篇 |
2001年 | 36325篇 |
2000年 | 36894篇 |
1999年 | 30377篇 |
1998年 | 7875篇 |
1997年 | 6662篇 |
1996年 | 6969篇 |
1995年 | 6627篇 |
1994年 | 6096篇 |
1993年 | 5589篇 |
1992年 | 22967篇 |
1991年 | 22924篇 |
1990年 | 22309篇 |
1989年 | 22076篇 |
1988年 | 20035篇 |
1987年 | 19417篇 |
1986年 | 18467篇 |
1985年 | 17306篇 |
1984年 | 12697篇 |
1983年 | 10741篇 |
1982年 | 5921篇 |
1979年 | 11518篇 |
1978年 | 8128篇 |
1977年 | 6832篇 |
1976年 | 6594篇 |
1975年 | 7268篇 |
1974年 | 8498篇 |
1973年 | 8141篇 |
1972年 | 7658篇 |
1971年 | 7127篇 |
1970年 | 6877篇 |
1969年 | 6306篇 |
1968年 | 5780篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Familial expansile osteolysis: a morphological, histomorphometric and serological study. 总被引:1,自引:0,他引:1
Biopsies from the diseased bones of patients with familial expansile osteolysis (FEO) were examined by light and electron microscopy. Focal concentrations of multinuclear osteoclasts were present, and these contained viral-like microcylindrical inclusions which appeared exclusive to their nuclei. No consistent relationship was found between osteoclast size and the number of osteoclast nuclei containing microcylindrical inclusions. Quantitative histomorphometry showed evidence of increased bone remodelling with high bone cell densities and a decrease of the reversal period in bone remodelling. The lesions contained prominent woven bone and fibrovascular tissue, together with mononuclear cells and adipocytes. Little bone was found in the most radiolucent lesions, which were almost totally occupied by adipocytes and fibrovascular tissue. Serology did not reveal any significant differences between the viral antibody titres of patients and their age- and sex-matched controls. The present study suggests that intranuclear viral-like microcylindrical inclusions of osteoclasts are not a specific feature of Paget's disease, and are found in other disorders of osteoclast function, including pycnodysostosis, osteopetrosis, giant cell tumours, and familial expansile osteolysis. 相似文献
92.
Measurement of cerebral monoamine oxidase B activity using L-[11C]deprenyl and dynamic positron emission tomography 总被引:3,自引:0,他引:3
A A Lammertsma C J Bench G W Price J E Cremer S K Luthra D Turton N D Wood R S Frackowiak 《Journal of cerebral blood flow and metabolism》1991,11(4):545-556
A tracer kinetic procedure was developed for the measurement of monoamine oxidase type B (MAO-B) activity using L-[11C]deprenyl and positron emission tomography (PET). The kinetic model consisted of two tissue compartments with irreversible binding to the second compartment (three rate constants). In addition, a blood volume component was included. Special attention was given to the accurate measurement of the plasma and whole blood input functions. The method was applied to the measurement of the dose-response curve of a reversible MAO-B inhibitor (Ro 19-6327). From the results, it followed that the rate constant for irreversible binding (k3) appeared to be a better index of MAO-B activity than the net influx constant Ki. Furthermore, regional analysis demonstrated that Ki, but not k3, was flow dependent. This implies that full kinetic analysis is required for an accurate assessment of MAO-B activity. 相似文献
93.
O. GAROFALO P. G. E. KENNEDY M. SWASH† J. E. MARTIN† P. LUTHERT B. H. ANDERTON P. N. LEIGH 《Neuropathology and applied neurobiology》1991,17(1):39-45
The expression of two heat shock proteins, HSP72 and p57, in addition to ubiquitin, has been studied immunocytochemically in nine amyotrophic lateral sclerosis (ALS) cases and 10 age-matched controls. HSP72 and p57 antibodies did not identify the characteristic ubiquitin-immunoreactive inclusions present in anterior horn cells in ALS spinal cord. Antibodies to HSP72, but not to p57 or ubiquitin, strongly labelled structures corresponding to polyglucosan bodies in spinal grey matter. Such immunoreactive profiles were more abundant in ALS cases, although they were also present in control material. They were sometimes identified by haematoxylin and eosin and periodic acid Schiff reaction, but were not labeled by phosphotungstic acid haematoxylin or by antibodies to glial fibrillary acidic protein. Although ubiquitin, HSP72 and p57 are stress-induced proteins, they are expressed differently and might therefore have different significance in neuronal degeneration. 相似文献
94.
Bronchoalveolar lavage fluid neutrophils were studied by the cytologic methods in 58 patients with chronic bronchitis, 63 ones with bronchiectasis, and 8 normal controls. The study included cytospectrophotometry of myeloperoxidase and alkaline phosphatase activity and estimation of active oxygen-producing cells in the NBT test. Neutrophilic functional activity was different in the patients with chronic bronchitis and bronchiectasis. Neutrophilic myeloperoxidase and alkaline phosphatase activities were lower in the patients with chronic bronchitis than in those with bronchiectasis, whereas the counts of cells active in the NBT test were low in both patient populations. 相似文献
95.
A 65-year-old man with spontaneous rupture of the esophagus survived with a direct suture of the esophagus 15 hours after the onset of symptoms. Endoscopic examination of the esophagus was especially of great help in determining the surgical procedure in this patient, and we want to stress the importance of prompt diagnosis and immediate surgery for this disease. 相似文献
96.
To investigate the simultaneous effects of dexamethasone on peripheral and central adrenocorticotropic hormone (ACTH) systems, rats were treated with dexamethasone or saline for 4 days. Pituitary, plasma, hypothalamus and cerebrospinal fluid (CSF) were then collected and analyzed for ACTH immunoreactivity. Additionally, hypothalamic tissue extracts were analyzed for corticotropin-releasing hormone (CRH) immunoreactivity. Dexamethasone significantly lowered peripheral levels of ACTH as measured in pituitary and plasma. Hypothalamic ACTH content significantly increased while CSF ACTH significantly decreased with dexamethasone treatment. Hypothalamic CRH concentrations showed a small but statistically insignificant decrease. These results suggest that prolonged exposure to dexamethasone affects central as well as peripheral ACTH activity, corroborate our previous findings in rhesus monkeys of decreased CSF ACTH in response to prolonged dexamethasone treatment, suggest that dexamethasone may inhibit the release of ACTH from hypothalamic neurons into the CSF, and provide evidence that the effect of dexamethasone on pituitary ACTH content is of greater magnitude than its effect on hypothalamic CRH. 相似文献
97.
V K Ryzhkov N A Borisova E M Gapchenko I A Dmitrieva 《Vestnik khirurgii imeni I. I. Grekova》1986,136(1):11-14
Roentgen endovascular occlusion with spiral emboli was used in 240 patients with different diseases. The introduction of spiral emboli into the arteries of abdominal and retroperitoneal organs was fulfilled through usual angiographic catheters. Duration of the arterial occlusion was checked up in the following angiographic examinations and showed the devices described to be appropriate for a continuous arterial blockade. No complications resulting from the introduction of the spiral embolus were noted. 相似文献
98.
D N Fairbanks 《American family physician》1986,33(2):205-211
Snoring means obstructive breathing during sleep, and its most exaggerated form is obstructive sleep apnea. Mild snoring may respond to simple self-help remedies. Heavy snoring responds well to the surgical removal or reconstruction of obstructive elements in the hypopharynx, nasopharynx or nasal passages. 相似文献
99.
K Mahmood M N Chowdhury E A Ayoola I A Mofleh R S Rashed F Z Faleh 《Tropical gastroenterology》1991,12(4):188-191
Seventy seven antral biopsies were collected from patients attending endoscopy clinic at King Khalid University Hospital, Riyadh, Saudi Arabia during a period of six months between December 1988 to May 1989. Of these 69 (89.6%) showed chronic gastritis as well as Helicobacter-like organisms (HLOs) in the biopsy specimens while 63 (81.8%) of biopsies grew Helicobacter pylori on culture. These findings indicate a good correlation between the histological diagnosis of chronic gastritis and isolation of H. pylori on culture. 相似文献
100.
The authors suggest additional criteria evidencing inflammations in the gallbladder and colloid stability of the bile: bile acid absorption and cholesterol sedimentation coefficients. Derivation of these coefficients is based on biochemical examination of the bile with measurements of bile acid, cholesterol, and bilirubin concentrations in both portions. The results of examinations of 99 subjects evidence the diagnostic value and specificity of the characteristics, and availability of this method for clinical practice. 相似文献