全文获取类型
收费全文 | 44788篇 |
免费 | 2527篇 |
国内免费 | 111篇 |
专业分类
耳鼻咽喉 | 674篇 |
儿科学 | 2037篇 |
妇产科学 | 1023篇 |
基础医学 | 5452篇 |
口腔科学 | 1924篇 |
临床医学 | 4075篇 |
内科学 | 9194篇 |
皮肤病学 | 1118篇 |
神经病学 | 3756篇 |
特种医学 | 1392篇 |
外国民族医学 | 2篇 |
外科学 | 7001篇 |
综合类 | 155篇 |
一般理论 | 17篇 |
预防医学 | 2815篇 |
眼科学 | 1294篇 |
药学 | 2917篇 |
中国医学 | 184篇 |
肿瘤学 | 2396篇 |
出版年
2024年 | 43篇 |
2023年 | 351篇 |
2022年 | 320篇 |
2021年 | 817篇 |
2020年 | 548篇 |
2019年 | 866篇 |
2018年 | 1358篇 |
2017年 | 964篇 |
2016年 | 1077篇 |
2015年 | 1043篇 |
2014年 | 1316篇 |
2013年 | 2028篇 |
2012年 | 3116篇 |
2011年 | 3578篇 |
2010年 | 1815篇 |
2009年 | 1294篇 |
2008年 | 3040篇 |
2007年 | 3245篇 |
2006年 | 3152篇 |
2005年 | 3192篇 |
2004年 | 3037篇 |
2003年 | 2811篇 |
2002年 | 2688篇 |
2001年 | 900篇 |
2000年 | 989篇 |
1999年 | 641篇 |
1998年 | 379篇 |
1997年 | 310篇 |
1996年 | 249篇 |
1995年 | 217篇 |
1994年 | 189篇 |
1993年 | 172篇 |
1992年 | 147篇 |
1991年 | 120篇 |
1990年 | 118篇 |
1989年 | 111篇 |
1988年 | 96篇 |
1987年 | 81篇 |
1986年 | 94篇 |
1985年 | 61篇 |
1984年 | 71篇 |
1983年 | 69篇 |
1982年 | 62篇 |
1981年 | 51篇 |
1980年 | 57篇 |
1979年 | 69篇 |
1978年 | 49篇 |
1977年 | 51篇 |
1974年 | 41篇 |
1973年 | 43篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
The relaxant effects of electrical field stimulation (EFS) and exogenously applied acetylcholine (ACh) or acidified NaNO2 (a-NaNO2) were investigated in the isolated mouse corpus cavernosum precontracted with phenylephrine hydrochloride (PE). Tetrodotoxin (TTX) blocked the relaxant effects of EFS completely, whereas it had no effect on the responses to ACh or a-NaNO2. Guanethidine and indomethacin failed to affect the electrically or ACh-induced relaxations. Atropine completely blocked the effect of ACh; however, it caused a slight reduction in the relaxation evoked by EFS.N
G- Nitro-l-arginine (l-NOARG) reduced the effects of EFS and ACh significantly, but it was ineffective on the relaxations induced by a-NaNO2. The inhibitory action ofl-NOARG was partly restored byl-arginine, but not byd-arginine. Methylene blue (MB) and hydroxocobalamin (HC) exhibited significant inhibition on the relaxations evoked by EFS, ACh and a-NaNO2. Hydroquinone (HQ) reduced relaxation due to a-NaNO2, but did not affect that of EFS and ACh. Our findings suggest that EFS-induced relaxations of mouse cavernosal tissue are mediated by a transmitter which probably resembles an organic nitrate. 相似文献
62.
63.
A. Koşar K. Sarica B. Küpeli G. Alçiğir O. Süzer S. Küpeli 《International urology and nephrology》1997,29(3):351-356
Infertility may occur in patients with unilateral testicular torsion whose contralateral testis is intact. Depending on this
observation, the physicians have begun to examine the contralateral testis.
In the present prospective study we aimed to examine the histopathologic alterations occurring in the contralateral testicle
with time. Sixty adult male albino rats were included in the programme, and following experimental torsion the histopathologic
findings, especially those in the contralateral testis, were evaluated after 4–12 weeks. Long-term and high degree torsion
of the testicle led to varying degrees of deterioration in the germinal epithelium and interstitial cells of the contralateral
testicle. Histopathologic alterations were reversed in 12 weeks. Tubular diameter and testicular volume also decreased in
accordance with the histopathologic alteration.
In our opinion, orchiectomy following torsion of one testicle will limit potential histopathologic alterations in the contralateral
testicle. 相似文献
64.
65.
Bülent Gül Sezer Kulaçoglnu Dr. Muammer Yükse Handan Dogan Ali Ihsan Ökten 《Neurosurgical review》1997,20(1):59-61
Esthesioneuroblastoma is an uncommon malignant neoplasm that arises from olfactory mucosa, often with intracranial extension.A case report of the youngest victim in the literature (2-year-old boy) is presented. 相似文献
66.
Jane McCusker MD Dr PH Elizabeth Healey MEd François Bellavance PhD Brian Connolly MD 《Academic emergency medicine》1997,4(6):581-588
Objective: To determine which characteristics of older patients who use a hospital ED are associated with repeat visits during the 90 days following the index visit.
Methods: The study was conducted in the ED of a 400-bed university-affiliated acute care community hospital in Montreal. Patients aged ≥75 years who visited the ED between 08:00 and and 16:00 on a convenience sample of days over an 8-week period (July and August 1994) were assessed using a questionnaire, physical and cognitive status instruments, and a functional problem checklist. The hospital's administrative database was used to identify repeat visits during the 90 days following the ED visit. The representativeness of the sample was assessed by analyses of ED visits made by 4,466 persons aged ≥65 years during a 12-month period (September 1993 to August 1994) using the hospital's administrative database.
Results: 256 patients aged ≥75 years visited the ED during the study period and 167 were assessed. Of these, 54 (32%) were admitted to the hospital. Among the 113 patients released from the ED, 27 (24%) made repeat visits during the next 90 days. In univariate analyses, repeat visits were significantly associated with the number of functional problems, cognitive impairment, and previous ED visits. In multiple logistic regression, male gender, living alone, and number of functional problems were independent predictors of repeat visits. In the administrative data analyses, nighttime arrival to the ED for the index visit was significantly associated with repeat visits.
Conclusions: Self-reported risk factors can help to identify a group of elders likely to make repeated ED visits; the development of a screening instrument incorporating questions on these problems and implementation of appropriate interventions might improve these patients' quality of life and reduce the demand for further ED care in this age group. 相似文献
Methods: The study was conducted in the ED of a 400-bed university-affiliated acute care community hospital in Montreal. Patients aged ≥75 years who visited the ED between 08:00 and and 16:00 on a convenience sample of days over an 8-week period (July and August 1994) were assessed using a questionnaire, physical and cognitive status instruments, and a functional problem checklist. The hospital's administrative database was used to identify repeat visits during the 90 days following the ED visit. The representativeness of the sample was assessed by analyses of ED visits made by 4,466 persons aged ≥65 years during a 12-month period (September 1993 to August 1994) using the hospital's administrative database.
Results: 256 patients aged ≥75 years visited the ED during the study period and 167 were assessed. Of these, 54 (32%) were admitted to the hospital. Among the 113 patients released from the ED, 27 (24%) made repeat visits during the next 90 days. In univariate analyses, repeat visits were significantly associated with the number of functional problems, cognitive impairment, and previous ED visits. In multiple logistic regression, male gender, living alone, and number of functional problems were independent predictors of repeat visits. In the administrative data analyses, nighttime arrival to the ED for the index visit was significantly associated with repeat visits.
Conclusions: Self-reported risk factors can help to identify a group of elders likely to make repeated ED visits; the development of a screening instrument incorporating questions on these problems and implementation of appropriate interventions might improve these patients' quality of life and reduce the demand for further ED care in this age group. 相似文献
67.
Efficient RT-PCR on platelet mRNA after long-term storage 总被引:1,自引:0,他引:1
We have developed a procedure permitting RT-PCR from mRNA even after a long-term storage (1 year) of platelet samples in ethanol (EtOH-platelets) at −80°C. To validate our method, we have analysed the human platelet alloantigen system (HPA-1) which is coded by β3 mRNA. We have also demonstrated the efficiency of amplification of part of the coding region for (i) αIIb subunit mRNA, (ii) αv subunit mRNA, and (iii) the seven transmembrane domain thrombin receptor mRNA. 相似文献
68.
69.
Michelle McKerral Pierre Lachapelle François Tremblay Robert C. Polomeno Marie-Sylvie Roy Raquel Beneish Franco Leporé 《Documenta ophthalmologica. Advances in ophthalmology》1995,91(2):181-193
The contribution of each monocular pathway to the timing of the binocular pattern visual evoked potential was assessed in situations where a significant interocular timing discrepancy was observed. Monocular and binocular pattern visual evoked potentials to 0.5° checks were recorded from normal subjects, normal subjects in whom one eye was blurred, patients with monocular amblyopia, and patients with resolved unilateral optic neuritis. Normal subjects showed facilitation, while suppression was evidenced in subjects with monocular blurring. In patients with amblyopia, the affected pathway had no effect on binocular pattern visual evoked potential latency, suggesting that the amblyopic eye was suppressed. In contrast, all patients with optic neuritis showed binocular averaging. Our results show that different forms of binocular interaction are evidenced in normal subjects, in amblyopia and in optic neuritis, and suggest that a comparative analysis of monocular and binocular pattern visual evoked potential peak times brings valuable information to the clinical evaluation that could be used to distinguish disease processes further.Abbreviation BPVEP
binocular pattern visual evoked potential 相似文献
70.
Fran?ois Hains Ann K Dzus J David Cassidy 《The Journal of the Canadian Chiropractic Association》1992,36(2):91-95
Neurological impairment secondary to spinal dysraphism most commonly presents as unilateral cavovarus foot in children. The deformity usually develops in the growing child around the age of five or six. The presence of a cavovarus foot of unknown origin in a child should lead to a complete neurological examination, including an assessment of the spine for spinal dysraphism. The early recognition of pathology may prevent severe neurological sequelae. A case of lipomyelomeningocele is presented to illustrate that cord damage in children with spinal dysraphism can present initially as a cavovarus foot. 相似文献