全文获取类型
收费全文 | 9519篇 |
免费 | 485篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 120篇 |
儿科学 | 801篇 |
妇产科学 | 381篇 |
基础医学 | 1045篇 |
口腔科学 | 200篇 |
临床医学 | 491篇 |
内科学 | 1748篇 |
皮肤病学 | 154篇 |
神经病学 | 336篇 |
特种医学 | 242篇 |
外科学 | 1872篇 |
综合类 | 282篇 |
一般理论 | 4篇 |
预防医学 | 369篇 |
眼科学 | 640篇 |
药学 | 515篇 |
1篇 | |
中国医学 | 27篇 |
肿瘤学 | 803篇 |
出版年
2023年 | 73篇 |
2022年 | 170篇 |
2021年 | 340篇 |
2020年 | 183篇 |
2019年 | 232篇 |
2018年 | 319篇 |
2017年 | 224篇 |
2016年 | 278篇 |
2015年 | 248篇 |
2014年 | 347篇 |
2013年 | 440篇 |
2012年 | 622篇 |
2011年 | 620篇 |
2010年 | 396篇 |
2009年 | 283篇 |
2008年 | 482篇 |
2007年 | 522篇 |
2006年 | 497篇 |
2005年 | 400篇 |
2004年 | 327篇 |
2003年 | 315篇 |
2002年 | 256篇 |
2001年 | 220篇 |
2000年 | 217篇 |
1999年 | 196篇 |
1998年 | 92篇 |
1997年 | 60篇 |
1996年 | 48篇 |
1995年 | 48篇 |
1992年 | 96篇 |
1991年 | 96篇 |
1990年 | 75篇 |
1989年 | 72篇 |
1988年 | 71篇 |
1987年 | 74篇 |
1986年 | 81篇 |
1985年 | 105篇 |
1984年 | 56篇 |
1983年 | 57篇 |
1982年 | 40篇 |
1981年 | 37篇 |
1980年 | 36篇 |
1979年 | 81篇 |
1978年 | 46篇 |
1977年 | 47篇 |
1976年 | 42篇 |
1975年 | 35篇 |
1974年 | 42篇 |
1973年 | 48篇 |
1972年 | 46篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
12.
This study was conducted to determine the occurrence of menstrual-linked asthma (MLA) in India in 100 consecutive female asthmatics in the reproductive age group. The patients were required to respond to a questionnaire concerning the relationship between their asthma and the menstrual cycle. Twenty-three patients had subjective perception of deterioration in symptoms of asthma in relation to the menstrual cycle. Ten patients from both groups were also required to maintain a daily peak expiratory flow rate (PEFR) diary for 2 consecutive menstrual cycles. The mean total duration of illness in patients with MLA was significantly longer than in patients without cyclic exacerbation. Cough and breathlessness were also significantly more severe as was the disease. This was evidenced by the more frequent emergency room visits and hospitalizations in these patients. Menstrual-linked worsening of asthma was most common in the premenstrual week (17 patients). In 8 of these 17 patients, this phenomenon continued to occur during the menstrual week also. Interestingly, 1 patient complained of deterioration of asthma 2 days after menstruation was over. Such an observation is yet to be recorded. Fourteen patients reported an increase in symptoms with almost every cycle while 3 had worsening related to specific season only. Sixteen patients often required extra medication during the premenstrual and/or menstrual weeks. A significant association was also observed between severity of premenstrual syndrome and MLA. The mean PEFR values over 2 cycles revealed a significant fall in the morning as well as evening values in the premenstrual and menstrual weeks as compared to the midcycle week in patients with MLA. This fall was maximal in the premenstrual week. Such a fall was not observed in asthmatics without menstrual exacerbation of symptoms. MLA was detected in about a fourth of the female asthmatics in India and it appears to represent a more severe form of the disease. This study also documented that MLA was associated with an increase in airway resistance and was not simply due to an increased perception of symptoms during the premenstrual or menstrual weeks. 相似文献
13.
Wasif Ali Deepak K. Agarwal Sadiq S. Sikora Bhagwant R. Mittal Narendra Krishnani Md. Ibrarullah Ramesh K. Gupta Satyendra P. Kaushik 《Surgery today》1997,27(3):247-250
Duodenogastric reflux (DGR) has been implicated in several disease processes. The present study was carried out to document the incidence and evaluate the clinical significance of DGR after choledochoduodenostomy (CDD). A total of 13 patients who had undergone cholecystectomy with a standard side-to-side CDD for choledocholithiasis or chronic pancreatitis were studied by symptom evaluation, scintigraphy, endoscopy, and gastric mucosal histology at least 6 months after surgery. The scintigraphic findings were then compared with those of 10 patients who had undergone cholecystectomy alone. Only two patients (15%) had mild dyspeptic symptoms. The incidence of DGR after CDD was 69% compared to 20% in the cholecystectomy alone group (P < 0.05). In the majority of patients the DGR was only mild to moderate and the severity correlated well with the degree of endoscopic gastritis, but not with the clinical symptoms or histological findings. These results indicate that while CDD is associated with a high incidence of DGR, its occurrence does not produce significant clinical symptoms. 相似文献
14.
15.
16.
The clinical profile of acute rheumatic fever in developing countries is frequently reported to differ from that in developed countries. This probably arose because a distinction was not made between the manifestations of the initial attack and those of a recurrence. Here, we report the patterns of presentation and clinical features of 100 cases of carefully determined initial attacks of rheumatic fever. As many as half the patients had carditis, and, of these, 50% exhibited congestive cardiac failure. This high incidence arises because in developing countries with limited health-care facilities patients continue to be physically active during the long pre-admission period. The study confirms that the clinical profile of the initial attack of rheumatic fever in developing countries is in most respects not unlike that in developed countries. 相似文献
17.
18.
19.
V K Srivastava G Palit A K Agarwal K Shanker 《Pharmacological research communications》1987,19(9):617-628
Sixteen new compounds 2-methylamino substituted phenyl-3-substituted anilino 4 (3H) quinazolinones (3-18) were prepared. All the compounds were evaluated for their antiparkinsonian activity and compared with bromocriptine. Compounds 10,15 and 18 showed better activity. These compounds also bind with the dopamine receptors in striatal membrane preparations of rat brain. 相似文献
20.
Effect of compressive follower preload on the flexion-extension response of the human lumbar spine. 总被引:5,自引:0,他引:5
Avinash G Patwardhan Robert M Havey Gerard Carandang James Simonds Leonard I Voronov Alexander J Ghanayem Kevin P Meade Thomas M Gavin Odysseas Paxinos 《Journal of orthopaedic research》2003,21(3):540-546
Traditional experimental methods are unable to study the kinematics of whole lumbar spine specimens under physiologic compressive preloads because the spine without active musculature buckles under just 120 N of vertical load. However, the lumbar spine can support a compressive load of physiologic magnitude (up to 1200 N) without collapsing if the load is applied along a follower load path. This study tested the hypothesis that the load-displacement response of the lumbar spine in flexion-extension is affected by the magnitude of the follower preload and the follower preload path. Twenty-one fresh human cadaveric lumbar spines were tested in flexion-extension under increasing compressive follower preload applied along two distinctly different optimized preload paths. The first (neutral) preload path was considered optimum if the specimen underwent the least angular change in its lordosis when the full range of preload (0-1200 N) was applied in its neutral posture. The second (flexed) preload path was optimized for an intermediate specimen posture between neutral and full flexion. A twofold increase in flexion stiffness occurred around the neutral posture as the preload was increased from 0 to 1200 N. The preload magnitude (400 N and larger) significantly affected the range of motion (ROM), with a 25% decrease at 1200 N preload applied along the neutral path. When the preload was applied along a path optimized for an intermediate forward-flexed posture, only a 15% decrease in ROM occurred at 1200 N. The results demonstrate that whole lumbar spine specimens can be subjected to compressive follower preloads of in vivo magnitudes while allowing physiologic mobility under flexion-extension moments. The optimized follower preload provides a method to simulate the resultant vector of the muscles that allow the spine to support physiologic compressive loads induced during flexion-extension activities. 相似文献