全文获取类型
收费全文 | 844篇 |
免费 | 69篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 41篇 |
妇产科学 | 3篇 |
基础医学 | 77篇 |
口腔科学 | 11篇 |
临床医学 | 96篇 |
内科学 | 106篇 |
皮肤病学 | 11篇 |
神经病学 | 21篇 |
特种医学 | 130篇 |
外科学 | 75篇 |
综合类 | 49篇 |
预防医学 | 169篇 |
眼科学 | 38篇 |
药学 | 59篇 |
肿瘤学 | 49篇 |
出版年
2019年 | 8篇 |
2018年 | 9篇 |
2017年 | 7篇 |
2016年 | 7篇 |
2015年 | 9篇 |
2014年 | 21篇 |
2013年 | 28篇 |
2012年 | 22篇 |
2011年 | 17篇 |
2010年 | 15篇 |
2009年 | 28篇 |
2008年 | 34篇 |
2007年 | 38篇 |
2006年 | 39篇 |
2005年 | 32篇 |
2004年 | 46篇 |
2003年 | 28篇 |
2002年 | 14篇 |
2001年 | 35篇 |
2000年 | 20篇 |
1999年 | 22篇 |
1998年 | 42篇 |
1997年 | 29篇 |
1996年 | 32篇 |
1995年 | 26篇 |
1994年 | 23篇 |
1993年 | 22篇 |
1992年 | 20篇 |
1991年 | 20篇 |
1990年 | 22篇 |
1989年 | 10篇 |
1988年 | 16篇 |
1987年 | 14篇 |
1986年 | 15篇 |
1985年 | 19篇 |
1984年 | 11篇 |
1983年 | 14篇 |
1982年 | 8篇 |
1981年 | 7篇 |
1980年 | 17篇 |
1979年 | 10篇 |
1978年 | 10篇 |
1977年 | 4篇 |
1976年 | 6篇 |
1973年 | 9篇 |
1972年 | 5篇 |
1970年 | 6篇 |
1966年 | 5篇 |
1929年 | 4篇 |
1928年 | 4篇 |
排序方式: 共有940条查询结果,搜索用时 203 毫秒
1.
ZQ Yin MD SG Crewther PhD B Pirie BSc DP Crewther PhD 《Clinical & experimental ophthalmology》1997,25(4):107-109
Purpose: It was investigated whether alterations in neuronal structure and function occasioned by strabismic amblyopia also may be reflected in alterations in the expression on Y type neurons of a Cat-301 antibody sensitive antigen in the lateral geniculate nucleus (LGN) and cortex of our cat model of strabismic amblyopia. Methods/Results: The percentage of positively labelled cells was reduced in LGN laminae that received input from the deviated eye in strabismic amblyopic cats compared with normal cats. In the strabismic cortex, the density of immunopositive neurons was significantly reduced compared with normal, the effect being most pronounced in layer IV Conclusions: Despite previous physiological recordings indicating a decrease in X-cell associated acuity in strabismic amblyopia, the present findings imply that the changes in the early visual experience occasioned by strabismus also produce specific molecular changes in theY neuronal class. 相似文献
2.
3.
4.
5.
6.
A comprehensive anatomic and radiographic analysis of the peribursal fat plane in 12 cadavers confirmed that the fat plane seen on radiographs represents extrasynovial fat lining the subacromial bursa and documented the anatomic relations of the bursa. A three-part retrospective clinical evaluation of rotator cuff tears, calcific tendinitis, and rheumatoid arthritis was performed. Two osteoradiologists blindly graded the appearance of the peribursal fat plane with the shoulder in external versus internal rotation in 21 patients with arthrographically intact rotator cuffs and 21 patients with disrupted rotator cuffs. The peribursal fat plane was seen better with disrupted rotator cuffs. The peribursal fat plane was seen better with the shoulder in internal rotation and was seen in 60% of control subjects but only 21% of patients with rotator cuff tears. Partial or complete obliteration of this fat plane is a sensitive (79%) but less specific (60%) indicator of rotator cuff tears. Obliteration of the peribursal fat plane by inflammatory processes in adjacent tissues, including calcific tendinitis and rheumatoid arthritis, occurred with a high frequency. 相似文献
7.
AJK WILLIAMS R FRASER DP CHORLEY J DENT 《Journal of gastroenterology and hepatology》1996,11(5):500-505
Safe placement of nasogastric tubes requires reliable positioning of the tip of the tube within the stomach. Radiology and aspiration are currently used to confirm tube position, but suffer from significant problems of cost and efficacy, respectively. We have developed a novel method to locate the position of a catheter tip within the body, using the detection of a low energy electromagnetic field generated in a coil located in the catheter with an external hand-held unit (Cathlocator). In vitro, the unit detected the distance of the coil from the detector with an accuracy of 0.1 cm over a range of 4–12 cm. In vivo studies were performed in 11 healthy volunteers using a purpose-built manometric assembly that incorporated the signal generating coil in its tip. In all subjects the Cathlocator showed the position of the signal generating coil to be cranial to the xiphisternum when manometric and transmucosal potential difference criteria showed it to be located above the lower oesophageal sphincter. When the coil was within the stomach, the Cathlocator identified its position within the epigastric, umbilical and left hypochondrial regions of the abdomen. The distance of the coil from the surface was significantly greater when in the duodenum mean (±s.e.m. 7.6±0.3 cm; P<0.001) and oesophagus (8.6±0.2 cm; P<0.002) than the stomach (5.0±0.4 cm). In one subject studied twice there was a close correlation between the location and depth measured by the device on each occasion. The Cathlocator is a novel non-radiological device that has the potential to be useful in the placement of gastrointestinal catheters. 相似文献
8.
The vascularity of 49 renal masses (26 malignant and 23 benign lesions) was investigated with duplex Doppler ultrasound. Doppler signals obtained at the margins of renal masses were defined as "tumor signals" when the Doppler-shifted frequency of the lesion exceeded the frequency shift in the ipsilateral main renal artery. These exceeded 2.5 kHz with a 3-MHz insonating frequency. Among the 26 renal masses that subsequently proved to be malignant, tumor signals were obtained in 15 of 18 (83%) untreated renal cell carcinomas, in three of four Wilms tumors, and in two patients with metastases to the kidney, but not in the one patient with lymphoma. None of the 23 benign renal masses demonstrated tumor signals. Tumor vascularity in malignant lesions gives rise to abnormal, high-velocity, Doppler-shifted signals that can help in the differential diagnosis of renal masses. 相似文献
9.
Elliott L Heederik D Marshall S Peden D Loomis D 《The Journal of allergy and clinical immunology》2005,116(1):127-132
BACKGROUND: Laboratory animal allergy is a common illness among workers exposed to laboratory animals and can progress to symptoms of asthma. OBJECTIVES: This study evaluates the continuum of disease from allergy symptoms to asthma symptoms in a dynamic cohort of workers exposed to animals in a pharmaceutical company. METHODS: Data arose from annual questionnaires administered to workers in a surveillance program established to monitor exposure to animals and the development of allergy. The life-table method was used to compare asthma-free survival between workers with and without symptoms of allergy. A Cox proportional hazards model was used to examine the effects of covariates on the development of asthma. RESULTS: A total of 603 workers contributed 2527.4 person-years to the study over the 12.3-year period. The probabilities of experiencing asthma symptoms by the 11th year of follow-up were 0.367 for workers with allergy symptoms and 0.052 for those without allergy symptoms. The hazard ratio for asthma symptoms when comparing workers with and without allergy symptoms was 7.39 (95% CI, 3.29-16.60) after adjustment for sex and family history of allergy. Female subjects developed asthma at a rate 3.4 times that of male subjects. CONCLUSIONS: This study supports the hypothesis that laboratory animal allergy symptoms are a major risk factor for the development of asthma. It also suggests a heightened risk of asthma for women who work with laboratory animals, a finding that has not been previously reported. 相似文献
10.
Effect of carrier selection on immunogenicity of protein conjugate vaccines against Plasmodium falciparum circumsporozoites.
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
J U Que S J Cryz Jr R Ballou E Fürer M Gross J Young G F Wasserman L A Loomis J C Sadoff 《Infection and immunity》1988,56(10):2645-2649
Conjugate vaccines against the sporozoite stage of Plasmodium falciparum were synthesized by covalently coupling the recombinant protein R32 [with the one-letter amino acid code of MDP-[(NANP)15NVDP]2LR] to tetanus toxoid, cholera toxin, choleragenoid, and Pseudomonas aeruginosa toxin A. Conjugates were produced by using adipic acid dihydrazide as a spacer molecule and carbodiimide as a coupling agent. The molar ratio of R32 to carrier protein ranged from 2.5:1 to 8.4:1. These conjugates were found to be stable, nontoxic, and nonpyrogenic. When adsorbed onto Al(OH)3, all conjugates were capable of inducing anti-R32 antibody. Conjugates made with either cholera toxin or Pseudomonas aeruginosa toxin A were significantly more immunogenic than those constructed with tetanus toxoid or choleragenoid. However, the magnitude of the immune response to the R32 moiety was not governed by the antibody response to the carrier protein. 相似文献