全文获取类型
收费全文 | 901698篇 |
免费 | 62642篇 |
国内免费 | 2336篇 |
专业分类
耳鼻咽喉 | 12503篇 |
儿科学 | 28748篇 |
妇产科学 | 26206篇 |
基础医学 | 126822篇 |
口腔科学 | 24779篇 |
临床医学 | 75082篇 |
内科学 | 183439篇 |
皮肤病学 | 19029篇 |
神经病学 | 71582篇 |
特种医学 | 36483篇 |
外国民族医学 | 336篇 |
外科学 | 142433篇 |
综合类 | 19135篇 |
一般理论 | 250篇 |
预防医学 | 64831篇 |
眼科学 | 20099篇 |
药学 | 63946篇 |
中国医学 | 1799篇 |
肿瘤学 | 49174篇 |
出版年
2018年 | 9099篇 |
2017年 | 7200篇 |
2016年 | 7714篇 |
2015年 | 8759篇 |
2014年 | 12422篇 |
2013年 | 19258篇 |
2012年 | 25739篇 |
2011年 | 27353篇 |
2010年 | 16648篇 |
2009年 | 15837篇 |
2008年 | 26195篇 |
2007年 | 27793篇 |
2006年 | 28013篇 |
2005年 | 27530篇 |
2004年 | 26371篇 |
2003年 | 25549篇 |
2002年 | 25125篇 |
2001年 | 41417篇 |
2000年 | 42613篇 |
1999年 | 36318篇 |
1998年 | 9987篇 |
1997年 | 9176篇 |
1996年 | 9105篇 |
1995年 | 8462篇 |
1994年 | 8101篇 |
1993年 | 7594篇 |
1992年 | 28227篇 |
1991年 | 27018篇 |
1990年 | 26447篇 |
1989年 | 25373篇 |
1988年 | 23589篇 |
1987年 | 23211篇 |
1986年 | 22291篇 |
1985年 | 21187篇 |
1984年 | 15832篇 |
1983年 | 13496篇 |
1982年 | 8105篇 |
1979年 | 14615篇 |
1978年 | 10235篇 |
1977年 | 8644篇 |
1976年 | 8167篇 |
1975年 | 8976篇 |
1974年 | 10720篇 |
1973年 | 10202篇 |
1972年 | 9680篇 |
1971年 | 8933篇 |
1970年 | 8599篇 |
1969年 | 8048篇 |
1968年 | 7702篇 |
1967年 | 7100篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
K D Blumberg W C Foster J F Blumberg R S Adelaar M E Deblois R W Hussey T P Loughran J A Cardea 《The Journal of bone and joint surgery. American volume》1990,72(7):1019-1024
Seventy-three fractures of the femoral shaft (seventy patients) were randomized to treatment with interlocked nailing with either the Brooker-Wills femoral nail (thirty-nine fractures) or the Russell-Taylor femoral nail (thirty-four fractures). Sixty-one patients (sixty-four fractures) were prospectively followed from admission until healing of the fracture. Specific attention was paid to recording operative details, including technical difficulties associated with insertion of the nails. Technical difficulties were encountered in insertion of the proximal screw, distal screw, and nail, and in deployment of the fins. Insertion of the Russell-Taylor nail was associated with less technical difficulty, operative time, and estimated loss of blood. The two nails differ in their biomechanical properties, methods of fixation, and instrumentation. These differences did not affect the clinical outcome; the fractures in both groups of patients healed with excellent functional results. 相似文献
952.
8-OH-DPAT and buspirone analogs inhibit the ketanserin-sensitive quipazine-induced head shake response in rats 总被引:2,自引:0,他引:2
F D Yocca R N Wright R R Margraf A S Eison 《Pharmacology, biochemistry, and behavior》1990,35(1):251-254
Behavioral syndromes mediated by serotonergic mechanisms may reflect interactions between distinct effects initiated by specific 5-HT receptors, such as the 5-HT1A and the 5-HT2 receptor. This hypothesis was tested by examining the effect of various 5-HT1A agonists on the 5-HT2 receptor-mediated quipazine-induced head shake response in rats. Subcutaneous administration of 8-OH-DPAT, buspirone, gepirone, and ipsapirone produced a dose-dependent inhibition of the ketanserin-sensitive quipazine-induced head shake response. These effects were produced by doses of agonists which did not induce reciprocal forepaw treading. Furthermore, pretreatment with a partial 5-HT1A agonist (+/-)pindolol blocked the inhibitory effects of 8-OH-DPAT to the level of inhibition produced by (+/-)pindolol itself. These results suggest that stimulation of central 5-HT1A receptors can modulate the expression of a central 5-HT2 receptor-mediated behavior. 相似文献
953.
M H Boevé J S van der Linde-Sipman F C Stades G F Vrensen 《Investigative ophthalmology & visual science》1990,31(9):1886-1894
This report provides transmission electron microscopic observations on the early pathogenesis of persistent hyperplastic tunica vasculosa lentis/persistent hyperplastic primary vitreous (PHTVL/PHPV) in affected canine fetuses at days 28-44 postcoitum. The retrolental tissue by which this anomaly is characterized consists of loosely arranged fibroblasts in a randomly oriented meshwork of collagenous fibrils. Some of these cells contain melanosomes at day 44. In one day-44 eye, cells of neuroectodermal origin (Müller cells; fibrous astrocytes) were observed. From day 37 onward, the posterior subcapsular part of the lens contains rounded, increased intercellular spaces, resembling vacuoles, which deform the shape of the lens fibers. The posterior lens capsule develops normally until day 30. From day 35 onward the capsule has an amorphous ultrastructure, as opposed to the clearly laminated ultrastructure in reference eyes at day 35. In addition, the capsule's thickness increases until day 35, and, instead of growing thicker, decreases thereafter. Based on these results, it is hypothesized that a primary metabolic disorder in the lens fibers, subsequently leading to the formation of an abnormal posterior lens capsule, constitutes the primary defect in the sequence of events leading to PHTVL/PHPV. 相似文献
954.
J W McLaren S D Trocme S Relf R F Brubaker 《Investigative ophthalmology & visual science》1990,31(2):339-346
Measurement of light scattered in the anterior chamber can provide important clinical information about the eye. In this study, a scanning ocular spectrofluorophotometer was used to measure scattering in the anterior chamber. Pathologic scattering (flare) was induced by argon laser photocoagulation of the iris in pigmented rabbits. The spectrally corrected intensity of the flare in inflamed eyes decreased as the inverse 2.2 power of the wavelength of the illuminating beam. The strongest signal with this instrument was measured at 470 nm. Diurnal variation of normal and spontaneous scatter from the aqueous humor was measured in nine pigmented rabbits entrained to a 12-hr light/12-hr dark cycle and in eight human subjects. A technique is described for determining the rate of flow of aqueous humor from scattered light when the transfer rate of scattering substance into the anterior chamber is constant. This technique was used to study changes in flow over the diurnal cycle. The rate of flow in human subjects during sleep was 60% of the rate during waking hours. In rabbits, the rate was lowest (44% of maximum) during the 6 hr after the lights were turned on, and were greatest just before the lights were turned on. These findings confirm previous studies of the circadian rhythm of aqueous humor flow in rabbits and humans. 相似文献
955.
Four years of data are reported on the drug cost avoidance and the net cost savings associated with a clinical pharmacy intervention program. In 1986 the pharmacy department at a 324-bed nonprofit community medical center began a clinical intervention program by adding one full-time equivalent for providing clinical services. A new clinical pharmacist position was created in 1988. A reorganization in 1989 resulted in further increases in staffing, including the creation of a clinical coordinator position to oversee the intervention program, and in administrative time. Staff pharmacists self-report a broad range of interventions on a clinical documentation form. During the period 1986-1989, monthly data on the number of types of interventions recommended, the percentage of recommendations accepted by the medical staff, and drug cost avoidance were tabulated. Cost avoidance was calculated by subtracting the cost of therapy ordered by the physician from the cost of therapy initiated as a result of the intervention. Net drug cost savings were calculated by subtracting from cost avoidance the cost of pharmacist time required for performing the interventions. The average number of interventions per month ranged from 170 in 1986 to 292 in 1990. During an 18-month period before the clinical coordinator was added, average monthly cost avoidance and net savings were $4932 and $3739, respectively. Average monthly cost avoidance increased to $6244 and savings to $4644 in a 12-month period after the clinical coordinator was added. A four-year study of a clinical intervention program showed that the dollar value and impact outlasted the initial success expected for such programs. 相似文献
956.
Intracranial actinomycosis in juvenile patients
Case report and review of the literature 总被引:1,自引:0,他引:1
F. Puzzilli Maurizio Salvati Andrea Ruggeri Antonino Raco Roberto Bristot Stefano Bastianello Pierpaolo Lunardi 《Child's nervous system》1998,14(9):463-466
A case of actinomycotic brain infection in a juvenile patient is described. Cases of actinomycosis affecting the head and
neck are rare, particularly in juvenile patients. In this case complete resolution of the infection was achieved by means
of surgical treatment and prolonged antibiotic therapy. The authors emphasize the importance of a combined approach for treatment
of this unusual brain infection and stress the difficulties involved in the diagnosis of this pathology.
Received: 3 November 1997 相似文献
957.
F Pinto R Lencioni V Napoli R Petrucci C Vignali N Armillotta C Bartolozzi 《Journal of ultrasound in medicine》1996,15(10):697-704
We examined 334 legs in 167 consecutive patients with advanced peripheral ischemic disease using color Doppler sonography and angiography. Angiography revealed 714 lesions (369 nonsignificant stenoses, 297 significant stenoses, and 48 occlusions) in the 334 legs examined. Overall, color Doppler sonography revealed diagnostic agreement with angiography in 668 of 714 lesions (93.5%), including 343 of 369 (92.9%) nonsignificant stenoses, 279 of 297 (93.9%) significant stenoses, and 46 of 48 (95.8%) occlusions. Overestimation occurred in 26 of 369 (7%) nonsignificant stenoses and 3 of 297 (1%) significant stenoses. Underestimation was observed in 15 of 297 (5%) significant stenoses and in 2 of 48 (4.2%) occlusions. Peak systolic velocity ratio correlated better (P < 0.01) than peak systolic velocity with diameter reduction percentage as assessed at angiography. Color Doppler sonography is an accurate noninvasive method for evaluating patients with peripheral ischemic disease. 相似文献
958.
S. A. Baxendale W. van Paesschen P. J. Thompson A. Connelly J. S. Duncan W. F. Harkness S. D. Shorvon 《Epilepsia》1998,39(2):158-166
Summary: Purpose: Quantitative MRI techniques provide an unparalleled opportunity to examine in vivo the relationship between the extent and laterality of hippocampal pathology and associated neuropsychological deficits. The purpose of this study was to examine the nature of the relationship between quantitative measures of hippocampal pathology and neuropsychological measures, using a multivariate approach. Methods: We examined the relationship between two MRI measures of hippocampal structure; hippocampal volumes (HCvol) and T2 relaxation times (HCT2), and memory performance, in 80 presurgical temporal lobe epilepsy patients. Results: As a group, patients with left hippocampal sclerosis (LHS) performed more poorly that those with right hippocampal sclerosis (RHS) on immediate and delayed prose recall. In the group as a whole, right hippocampal volume was significantly correlated with the delayed recall of a complex figure. None of the verbal memory test scores were significantly correlated with the right or left HCvol or HCT2 measures. However, stepwise multiple regression analyses indicated that up to a third of the variation in specific test scores could be explained by the quantitative MRI hippocampal measures in conjunction with chronological age, and age at onset of habitual epilepsy. Left hippocampal measures explained 24% of the variance in the story-recall tasks, while right hippocampal measures explained 18% of the variance in a design-learning task and 32% of the variance in a figure-recall task. Conclusions: Our results provide some support for the lateralised model of material specific memory deficits, but suggest that a number of demographic and epilepsy-related factors may interact with the extent and laterality of hippocampal pathology in shaping the nature of the associated neuropsychological deficit. 相似文献
959.
Franco Rilke M. D. F. R. C. Umberto Veronesi M. D. Alberto Luini M. D. Cristina Brambilla M. D. Viviana Galimberti M. D. Stefano Zurrida M. D. Silvana Pilotti M. D. M. I. A. C. Silvana Di Palma M. D. Roberto Zucali M. D. Laura Lozza M. D. 《The breast journal》1996,2(3):176-180
Abstract: Breast conservation surgery is an effective and safe treatment for many breast carcinomas. It may be possible to further limit the extent of resection (or expand the indication for breast conservation) by the application of preoperative chemotherapy and radiotherapy. We explored the feasibility of this in a pilot study.
Seventy-three patients (mean age 48, 63% premenopausal) with confirmed breast cancer, less than 2.5 cm, received chemotherapy (Group A) or chemotherapy plus radiotherapy (Group B) prior to limited resection (tumorectomy). Axillary dissection was always performed. Results: In 6/31 (19%) Group A and 17/42 (40%) Group B patients the tumor was not palpable after preoperative treatment, with complete pathological remission in 1 and 3 cases respectively. Histologic grading, mitosis, cellular alteration, and cellularity evaluations indicated a consistently greater therapeutic effect with chemoradiotherapy than with chemotherapy alone.
In conclusion, radiotherapy appears useful in the preoperative treatment of breast cancer and its use in association with various drug combinations should be further explored. 相似文献
Seventy-three patients (mean age 48, 63% premenopausal) with confirmed breast cancer, less than 2.5 cm, received chemotherapy (Group A) or chemotherapy plus radiotherapy (Group B) prior to limited resection (tumorectomy). Axillary dissection was always performed. Results: In 6/31 (19%) Group A and 17/42 (40%) Group B patients the tumor was not palpable after preoperative treatment, with complete pathological remission in 1 and 3 cases respectively. Histologic grading, mitosis, cellular alteration, and cellularity evaluations indicated a consistently greater therapeutic effect with chemoradiotherapy than with chemotherapy alone.
In conclusion, radiotherapy appears useful in the preoperative treatment of breast cancer and its use in association with various drug combinations should be further explored. 相似文献
960.
Polymer-alanine dosimeters (PADs) have been irradiated, in air with a concentration of 5 ppm of ozone, with doses up to 10 kGy, by means of a 90Sr source. The electron spin resonance (ESR) signals were compared with the signals obtained after irradiations in normal air, and the amplitude reduction was found to be negligible. The evolution of the ESR signal of PADs irradiated in normal air and thereafter stored in air with 5 ppm ozone concentration was also investigated. No change was observed over a period of 2 months. 相似文献