全文获取类型
收费全文 | 36607篇 |
免费 | 1914篇 |
国内免费 | 152篇 |
专业分类
耳鼻咽喉 | 487篇 |
儿科学 | 674篇 |
妇产科学 | 409篇 |
基础医学 | 4575篇 |
口腔科学 | 1140篇 |
临床医学 | 2533篇 |
内科学 | 8450篇 |
皮肤病学 | 768篇 |
神经病学 | 3400篇 |
特种医学 | 1838篇 |
外国民族医学 | 1篇 |
外科学 | 5842篇 |
综合类 | 129篇 |
一般理论 | 6篇 |
预防医学 | 1144篇 |
眼科学 | 753篇 |
药学 | 2325篇 |
中国医学 | 72篇 |
肿瘤学 | 4127篇 |
出版年
2023年 | 200篇 |
2022年 | 384篇 |
2021年 | 658篇 |
2020年 | 395篇 |
2019年 | 498篇 |
2018年 | 626篇 |
2017年 | 545篇 |
2016年 | 668篇 |
2015年 | 640篇 |
2014年 | 817篇 |
2013年 | 997篇 |
2012年 | 1650篇 |
2011年 | 1698篇 |
2010年 | 1037篇 |
2009年 | 892篇 |
2008年 | 1505篇 |
2007年 | 1740篇 |
2006年 | 1616篇 |
2005年 | 1535篇 |
2004年 | 1557篇 |
2003年 | 1450篇 |
2002年 | 1497篇 |
2001年 | 1322篇 |
2000年 | 1432篇 |
1999年 | 1279篇 |
1998年 | 487篇 |
1997年 | 387篇 |
1996年 | 363篇 |
1995年 | 308篇 |
1994年 | 303篇 |
1993年 | 278篇 |
1992年 | 990篇 |
1991年 | 853篇 |
1990年 | 810篇 |
1989年 | 804篇 |
1988年 | 758篇 |
1987年 | 757篇 |
1986年 | 667篇 |
1985年 | 623篇 |
1984年 | 423篇 |
1983年 | 343篇 |
1979年 | 296篇 |
1978年 | 198篇 |
1977年 | 177篇 |
1974年 | 188篇 |
1973年 | 162篇 |
1972年 | 161篇 |
1971年 | 181篇 |
1970年 | 155篇 |
1969年 | 176篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Naoko Iwakami Shin-ichiro Iwakami Munechika Hara Mitsuaki Sekiya Takashi Dambara Kazuhisa Takahashi 《Respiratory investigation》2018,56(3):238-242
Background
It is well known that ultrasound-guided needle-aspiration (USGNA) for intrapulmonary subpleural lesion in contact with the pleura is useful and safe, and its diagnostic yield is high. However, reports concerned with the analyses of cases with intrapulmonary subpleural lesion which could not be diagnosed using USGNA are limited. The objective of this study is to clarify the radiological properties of subpleural primary lung cancer which obstruct diagnosis by USGNA.Methods
The consecutive cases with subpleural primary lung cancer whose radiological properties could be confirmed by thoracic computed tomography (CT) without contrast enhancement (CE), and examined by USGNA at our hospital between January 1999 and December 2014 have been analyzed. All cases were given pathological diagnoses of primary lung cancer. The diagnostic yield by USGNA was calculated, and the properties of the lesions of the subjects were analyzed by means of thoracic CT without CE images and pathological findings.Results
87 consecutive cases (41–86 year olds, 75 males, 12 females) were analyzed. The overall diagnostic yield by USGNA was 86.2%. There was no statistically significant difference regarding the diagnostic yield concerning radiological properties such as cavities, small airspaces and low density areas in the lesions and their sizes. However, the diagnostic yield for the cases with squamous cell carcinoma was statistically significantly low (p=0.02).Conclusion
Although the diagnostic yield of USGNA is not distorted by the radiological properties of lesions, it is statistically significantly low in cases with squamous cell carcinoma. 相似文献992.
Recent studies have determined that expression of inflammatory mediators, such as cytokines and chemokines, is an important
factor in the development and progression of heart failure (HF). These inflammatory mediators are expressed in response to
various myocardial insults, including myocardial ischemia, viral infection, and toxins, and appear to have a detrimental effect
on cardiac function and prognosis in HF patients. Our previous reports have shown activation of inflammatory cytokines, particularly
tumor necrosis factor-α (TNF-α), in the myocardium and peripheral monocytes in patients with HF. Indeed, sustained increases
in cytokines, including TNF-α and its receptor, lead to monocyte phenotype transition, myocytic apoptosis, and activation
of matrix metalloproteinase. This in turn modifies the interstitial matrix, augmenting further ventricular remodeling. Thus,
in view of the emerging importance of TNF-α in the pathogenesis of HF, we review the effects of TNF-α on the physiology of
the heart and the development of clinical strategies to target the inflammatory cytokine cascade. 相似文献
993.
994.
The relationship between diabetic neuropathy on the one hand and microangiopathy and arteriosclerosis on the other was studied by determining plasma 6-keto-prostaglandin F1 alpha (PGF1 alpha) and plasma thromboxane B2 (TXB2) in diabetics with neuropathy. The subjects were 13 patients with insulin independent diabetes mellitus with polyneuropathy (DN+ group), 9 cases which had no neuropathy (DN- group) and 6 control cases. The patients with severe retinopathy, nephropathy and hypertension were excluded. Plasma 6-keto-PGF1 alpha and plasma TXB2 concentration were determined by radioimmunoassay. The motor neuron conduction velocity (M.C.V.) was measured through the tibial nerve in all diabetics. Plasma 6-keto-PGF1 alpha was 116.3 +/- 4.2 pg/ml (mean +/- SE) in the DN+ group and 139.9 +/- 3.0 in the DN- group, each group showing a significant fall over the control with 150.8 +/- 4.5. Plasma 6-keto-PGF1 alpha in the DN+ group showed a significant decrease in comparison with that in the DN- group. As to plasma TXB2, there was no significant difference among the three groups. The M.C.V. fell off significantly in the DN+ group with 52.9 +/- 3.2 m/sec. Furthermore, a significant positive correlation was observed between M.C.V. and plasma 6-keto-PGF1 alpha. The following is the summary of these results. A decrease in plasma 6-keto-PGF1 alpha was observed in diabetics with polyneuropathy. A decrease in the production of prostacyclin (PGI2) due to impairment of vascular endothelium in the nerve tissue was surmised. The decrease in plasma 6-keto-PGF1 alpha presumably stimulates the activity of platelet agglutination and causes an ischemic change in the nerve tissue.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
995.
996.
N Yoshida Y Takahashi M Mori K Saitou S Yokota S Mathuyama A Sugita 《Kansenshōgaku zasshi. The Journal of the Japanese Association for Infectious Diseases》1989,63(12):1333-1337
A 13 year-old girl with Down's syndrome was admitted to our hospital with a very positive reaction to PPD 5TU, abnormal shadow on the chest X-ray films and diarrhea. She suffered from acute enterocolitis one year ago, and then has been complaining of abdominal pain, appetite loss, and weight loss for a year. After admission, she was diagnosed as tuberculous pleuritis and suspected intestinal tuberculosis by laboratory examination. She recovered without sequelae by the combination therapy of SM, INH, and RFP, and was discharged after 5 months. The diagnosis of intestinal tuberculosis was confirmed by Colon Fiberscopy showing ulceration at the ileocecal region and simultaneous biopsy showing granuloma. Surgical treatment was not reserved, because she had no complications namely perforation and fistulization. We estimated that the onset of intestinal tuberculosis coincided with the acute enterocolitis which she had about one year ago. We realized the importance of paying attention to intestinal tuberculosis in the differential diagnosis of enterocolitis, especially regional enteritis. Furthermore, in the therapy of the immunocompromised host including Down's syndrome, we must pay attention to extra-pulmonary tuberculosis. Efficiency of SM for intestinal tuberculosis with complications was confirmed. 相似文献
997.
T Hirano P Prunet H Kawauchi A Takahashi T Ogasawara J Kubota R S Nishioka H A Bern K Takada S Ishii 《General and comparative endocrinology》1985,59(2):266-276
A highly specific radioimmunoassay (RIA) for the measurement of prolactin (PRL) in the plasma and pituitary of salmonid fishes was developed using a rabbit antiserum to chinook salmon (Oncorhynchus tschawytscha) PRL. The PRLs purified from chinook salmon and chum salmon (O. keta) pituitaries showed exactly the same competitive inhibition curves in the RIA, regardless of iodination of either hormone. The displacement curves for pituitary extracts and plasma from several salmonids, including chum, coho, and amago salmon, rainbow trout, and Japanese charr, were parallel to the salmon PRL standard, whereas those from the eel, goldfish, carp, and tilapia showed negligible cross-reactivity. Negligible cross-reactivity was also seen with plasma from hypophysectomized rainbow trout or coho salmon. None of the mammalian PRL or growth hormone (GH) preparations, bullfrog PRL, or presumptive chum salmon "gonadotropin" and eel "PRL" cross-reacted in the PRL RIA. Presumptive chum salmon GH showed less than 0.05% cross-reactivity. The RIA sensitivity was less than 0.1 ng of the salmon PRL standard per milliliter. The immunoreactive plasma PRL levels in mature chum salmon were below 1 ng/ml in seawater. The plasma PRL in females increased to about 8 ng/ml 1 day after transfer to fresh water, and high levels (2-4 ng/ml) were maintained during 3-7 days after the transfer. In contrast, when males were transferred to fresh water, an increase in plasma PRL was seen only 1 day after the transfer. A significant decrease in plasma osmolality was observed in both males and females after transfer to fresh water. No change was observed either in plasma PRL or osmolality, when fish were transferred from seawater to seawater. 相似文献
998.
Motoyasu Ishii Yutaka Miyazaki Takeshi Yamamoto Masahito Miura Yoshiyuki Ueno Tohru Takahashi Takayoshi Toyota 《Liver international》1993,13(4):227-231
ABSTRACT— A 50-year-old woman suffered from a diffuse skin rash, high fever and jaundice immediately after a second injection of glutathion and Stronger Neo-minophagen C which contains glycyrrhizin. Liver biopsy performed 11 months after the onset showed mild spotty hepatocyte necrosis, marked cholestasis in parenchyma, and some lymphocyte infiltration in the portal area. Interlobular bile ducts had undergone vacuolar degeneration or were absent in some portal tracts. In her hospital course, unremitting jaundice persisted and biliary cirrhosis developed with signs of portal hypertension; she died from liver failure 26 months after the onset. A liver specimen at her death revealed that most of the interlobular bile ducts had vanished. Based on the clinical course and pathology, drug-induced ductopenia, possibly due to an adverse reaction to glycyrrhizin, is the most likely diagnosis. While drug-related biliary cirrhosis is rarely fatal, this case presented an unusually rapid course of fatal biliary cirrhosis. 相似文献
999.
1000.
Roles of mechano-sensitive ion channels, cytoskeleton, and contractile activity in stretch-induced immediate-early gene expression and hypertrophy of cardiac myocytes. 总被引:5,自引:0,他引:5
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
J Sadoshima T Takahashi L Jahn S Izumo 《Proceedings of the National Academy of Sciences of the United States of America》1992,89(20):9905-9909
Mechanical loading of cardiac and skeletal muscles in vivo and in vitro causes rapid activation of a number of immediate-early (IE) genes and hypertrophy of muscle cells. However, little is known as to how muscle cells sense mechanical load and transduce it into intracellular signals of gene regulation. We examined roles of putative cellular mechanotransducers, mechanosensitive ion channels, the cytoskeleton, and contractile activity in stretch-induced hypertrophy of cardiac myocytes grown on a deformable silicone sheet. Using the patch-clamp technique, we found a single class of stretch-activated cation channel that was completely blocked by gadolinium (Gd3+). Inhibition of this channel by Gd3+ did not affect either the stretch-induced expression of IE genes or the increase in protein synthesis. Neither disruption of microtubules with colchicine nor that of actin microfilaments by cytochalasin D prevented the stretch-induced IE gene expression and increase in protein synthesis. Arresting contractile activity of myocytes by high K+, tetrodotoxin, or Ba2+ did not affect the stretch-induced IE gene expression. Tetrodotoxin-arrested myocytes could increase protein synthesis in response to stretch. These results suggest that Gd(3+)-sensitive ion channels, microtubules, microfilaments, and contractile activity may not be necessary for transduction of mechanical stretch into the IE gene expression and hypertrophy. The stimulus of membrane stretch may be transmitted to the cell nucleus through some mechanisms other than electrical or direct mechanical transduction in cardiac myocytes. 相似文献