全文获取类型
收费全文 | 16722篇 |
免费 | 849篇 |
国内免费 | 130篇 |
专业分类
耳鼻咽喉 | 185篇 |
儿科学 | 351篇 |
妇产科学 | 305篇 |
基础医学 | 2040篇 |
口腔科学 | 413篇 |
临床医学 | 1029篇 |
内科学 | 4510篇 |
皮肤病学 | 496篇 |
神经病学 | 1423篇 |
特种医学 | 637篇 |
外国民族医学 | 2篇 |
外科学 | 2483篇 |
综合类 | 76篇 |
一般理论 | 1篇 |
预防医学 | 830篇 |
眼科学 | 254篇 |
药学 | 978篇 |
中国医学 | 12篇 |
肿瘤学 | 1676篇 |
出版年
2023年 | 76篇 |
2022年 | 193篇 |
2021年 | 299篇 |
2020年 | 163篇 |
2019年 | 215篇 |
2018年 | 291篇 |
2017年 | 246篇 |
2016年 | 276篇 |
2015年 | 316篇 |
2014年 | 368篇 |
2013年 | 506篇 |
2012年 | 826篇 |
2011年 | 903篇 |
2010年 | 513篇 |
2009年 | 463篇 |
2008年 | 813篇 |
2007年 | 879篇 |
2006年 | 894篇 |
2005年 | 927篇 |
2004年 | 908篇 |
2003年 | 890篇 |
2002年 | 871篇 |
2001年 | 468篇 |
2000年 | 420篇 |
1999年 | 443篇 |
1998年 | 246篇 |
1997年 | 216篇 |
1996年 | 186篇 |
1995年 | 187篇 |
1994年 | 152篇 |
1993年 | 128篇 |
1992年 | 353篇 |
1991年 | 314篇 |
1990年 | 302篇 |
1989年 | 339篇 |
1988年 | 281篇 |
1987年 | 237篇 |
1986年 | 241篇 |
1985年 | 199篇 |
1984年 | 148篇 |
1983年 | 100篇 |
1982年 | 59篇 |
1980年 | 60篇 |
1979年 | 92篇 |
1978年 | 57篇 |
1977年 | 53篇 |
1975年 | 51篇 |
1974年 | 67篇 |
1973年 | 71篇 |
1972年 | 55篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
M Kitazawa M Akahane Y Nakano K Hayakawa K Sato M Kobayashi 《Yakugaku zasshi : Journal of the Pharmaceutical Society of Japan》1989,109(10):718-736
The derivatives (2) of 3-(2,3-dihydro-2,2-dimethyl-3-oxo-5-benzofuranyl) acrylic acid (2b) were synthesized. The compounds (3a-g) in which bromo, methoxy, nitro, amino or acetamido group was introduced on the benzene ring of the derivatives (2) and the compounds (3h-k) in which acryloyl moiety was introduced on the 6- or 7-position of the benzofuranone skeleton also synthesized. Furthermore, propionic acid derivatives (4a-c), acetic acid derivatives (4d-g), formic acid derivatives (4h-k) and oxyacetic acid derivatives (5) were prepared by converting the acryloyl moiety of the derivatives (2) into propionyl, acetyl, formyl and oxyacetyl groups. These compounds were tested for antiulcer activities. Among these compounds, 1-[3-(2,3-dihydro-2,2-dimethyl-3-oxo-5-benzofuranyl)acryloyl]piperidine (2d) and 4-[3-(2,3-dihydro-2,2-dimethyl-3-oxo-5-benzofuranyl)acryloyl] morpholine (2g) were found to have stronger antiulcer activities. 相似文献
62.
Marc G Weisskopf Honglei Chen Michael A Schwarzschild Ichiro Kawachi Alberto Ascherio 《Movement disorders》2003,18(6):646-651
Anxiety disorders are common in Parkinson's disease (PD). However, the risk of PD among people with anxiety has not been examined in a prospective cohort study. We examined this relation prospectively within the Health Professionals Follow-Up Study, a cohort of US male health professionals. In 1988, anxiety was assessed using the Crown-Crisp phobic anxiety index in 35,815 men without PD, stroke, or cancer at baseline. There were 189 incident cases of PD during 12 years of follow-up. After adjusting for age, smoking, and caffeine intake, the relative risk of PD among men with the highest level of anxiety (Crown-Crisp index scores of 4 and above) was 1.5 (95% CI = 1.0-2.1; P-trend = 0.01) compared to men with the lowest level of anxiety. This positive association persisted after excluding cases of PD with onset in the first 2 years of follow-up. Use of anxiolytic medication was also associated with an elevated risk of PD (RR= 1.6; 95% CI = 0.9-3.1), but adjusting for this potential confounder did not materially affect the association between anxiety and risk of PD. Our results suggest that anxiety is a risk factor for PD. Whether this association is causal or the result of shared underlying biology remains a question. 相似文献
63.
Influence of acetylcholine on neuronal activity of monkey amygdala during bar press feeding behavior
L zl L n rd Yutaka Oomura Yasuhiko Nakano Shuji Aou Hitoo Nishino 《Brain research》1989,500(1-2):359-368
Single neuron activity in the monkey amygdala was investigated during cue signalled conditioned bar press feeding behavior and the effects of electrophoretically applied acetylcholine (ACh) and atropine were analyzed. ACh increased the firing rate of one third of the neurons tested; these excitatory responses were inhibited by the muscarinic receptor antagonist atropine. No characteristic location of ACh-sensitive neurons was found, cells were diffusely distributed throughout the amygdala. Activity of ACh-sensitive neurons did not correlate with any particular event during the bar press feeding task. However, continuous application of ACh at low current intensity during the task significantly enhanced the task-related excitatory firing patterns, or markedly attenuated the inhibitory responses. Continuous application of atropine elicited or enhanced inhibitory response patterns. These results suggest that the cholinergic system of the monkey amygdala facilitates neuronal excitation but attenuates inhibition related to various phases of feeding behavior, such as to cue recognition, food aquisition and rewarding process. 相似文献
64.
65.
66.
N Yamada M Nakamura K Ishikura M Ota T Yazu N Hiraoka H Tanaka M Ito H Fujioka N Isaka T Nakano 《International angiology》2003,22(1):50-54
AIM: In Japan, acute pulmonary thromboembolism (APTE) is still rare, but the number of patients with APTE has been steadily increasing. It is important for early diagnosis and early management of APTE to recognize epidemiological characteristics of this condition. METHODS: We investigated the epidemiological characteristics of 252 patients with APTE who were admitted to our institutions between 1975 and 2001. APTE was more prevalent in women that in men. It was observed the most in the age group between 50s to 70s, especially in women. Many patients had prolonged immobilization, recent major operation, obesity, or cancer, as risk factors for venous thromboembolism. One hundred and thirty-eight patients developed APTE in hospital; 60 patients were in Department of Internal Medicine, 28 in General Surgery, 15 in Orthopedics, 15 in Obstetrics and Gynecology, and 20 in other services. RESULTS: Among 58 patients with malignancy, 43% had cancers in digestive organs, 21% in gynecological, and 17% in urological. Among 61 patients who were examined for the presence of thrombophilia, 13 patients had inherited thrombophilia (8 protein C deficiency, 4 protein S deficiency, and 1 antithrombin III deficiency) 11 had antiphospholipid antibodies which indicated thrombophilia. Five out of the above 61 patients (8%) had no obvious risk factors including thrombophilia. CONCLUSION: The findings in our patients were almost the same as those in Western patients, except for some points. These results might be useful to establish a preventive approach for APTE in Japan. 相似文献
67.
Einosuke Mizuta Toshihiro Hamada Shin-ichi Taniguchi Masaki Shimoyama Takahiro Nawada Junichiro Miake Yasuhiro Kaetsu Li Peili Kiyosuke Ishiguro Shingo Ishiguro Osamu Igawa Chiaki Shigemasa Ichiro Hisatome 《Hypertension research》2006,29(8):635-638
We report the case of a 67-year-old woman with severe hypertension caused by an extra-adrenal pheochromocytoma. The tumor was detected by 131I metaiodobenzylguanidine scintigraphy and it was found to be small (2 cm ?) by enhanced CT. After the extirpation of the tumor, the blood pressure of the patient immediately normalized. It should be taken into account that a small extra-adrenal pheochromocytoma can be one of the causes of secondary hypertension in elderly patients. Since small extra-adrenal pheochromocytomas are difficult to detect, it is also important to perform suitable examinations to establish the diagnosis. Furthermore, we emphasize the importance of an accurate diagnosis in elderly patients with pheochromocytoma, for they often have less symptomatology and more severe cardiovascular complications due to refractory hypertension than younger patients. 相似文献
68.
69.
70.
J Yamazaki H Ohsawa T Uchi M Iida M Wakakura K Okamoto H Hosoi T Morishita H Nakano Y Yabe 《呼吸と循環》1992,40(3):275-281
201Tl myocardial SPECT was performed in cases of dilated cardiomyopathy and valvular heart disease with left ventricular eccentric hypertrophy, and the two groups were compared from the standpoint of the mechanism of onset of myocardial disorders. Significant coefficients of correlation were seen between the Tl score and LVDd (r = 0.792, r = 0.785) and Tl score and LVEF (r = -0.634, r = -0.555) in both dilated cardiomyopathy and valvular heart disease. In cases of valvular heart disease, significant correlation coefficients (r = -0.756, r = -0.720) between LVDd and r-WR (relative-washout rate), and Tl score and r-WR were observed, but no such correlation was seen in dilated cardiomyopathy. In valvular heart disease, a decrease in myocardial perfusion associated with enlargement of the left ventricle appeared, while in dilated cardiomyopathy, there was a marked decrease in LVEF in proportion to the thallium defect. Therefore, it was assumed that left ventricular wall disorders occur due to myocardial metabolic disorders and coronary microcirculation disorders. 相似文献