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81.
This study is concerned with the nature and distribution of mineral in the gallbladder of a patient with chronic cholecystitis. Light and electron microscopic imaging revealed the mineral to be in the epithelial cells of the mucosa and fibroblasts of the submucosa. In the epithelial cells at the early stages of deposition, mineral was located in the nuclei and throughout the cytoplasm in association with interdigitating cell processes and apical microvilli but was absent in mitochondria. Elemental and electron diffraction analyses indicated the mineral inclusions to be apatite in nature. 相似文献
82.
应力松弛接骨板对骨几何形态和力学性能影响的实验观察 总被引:2,自引:0,他引:2
《中华医学杂志》1995,(7)
作者采用粘弹性材料制成垫圈置于接骨板螺孔与螺丝钉之间,构成应力松弛接骨板系统。实验证实,有垫与无垫接骨板在固定早期对模拟骨的应力遮挡作用相同,固定8周后垫圈出现明显变形和破坏,使有垫接骨板的应力遮挡率从第10周起明显低于无垫接骨板。有垫接骨板固定的胫骨骨质疏松明显轻于无垫组,固定20周后,有垫组的胫骨髓腔径明显小于无垫组,骨皮质厚度和胫骨抗弯强度均明显大于无垫组(P<0.05~0.01)。说明应力松弛接骨板系统早期具有与坚强接骨板相同的固定作用,后期其应力遮挡效应可逐渐减小,避免严重的骨质疏松和骨力学性能下降。 相似文献
83.
Emilio Bombardieri Antonia Martinetti Rosalba Miceli Luigi Mariani Maria Rita Castellani Ettore Seregni 《European journal of nuclear medicine and molecular imaging》1997,24(11):1349-1355
Bone scintigraphy plays a major role in the diagnosis of bone metastases. The clinical utility of new biochemical markers
of bone metabolism has recently been investigated in various bone diseases. This study evaluated the role of some bone metabolism
markers in comparison with bone scan in the follow-up of breast cancer patients. We studied 149 patients with breast cancer,
33 (22%) of whom had bone metastases. IRMAs were used for the evaluation of blood levels of osteocalcin, bone alkaline phosphatase
(BAP), the C-terminal propeptide of type I procollagen and the C-terminal cross-linked telopeptide of type I collagen (ICTP).
Multivariate regression analysis showed that menopausal status (P=0.007) and metastatic bone lesions (P=0.001) affected bone marker levels. When considering post-menopausal women, the only subset in which bone metabolism marker
behaviour could be reliably investigated, we found a high degree of overlap in marker distribution for scan-positive and scan-negative
patients. Discrimination between scan-negative and scan-positive patients based on the above markers, taken singly or jointly,
was assessed by means of logistic discriminant analysis. The best discrimination was achieved with BAP, closely followed by
ICTP. BAP and ICTP together gave a slight improvement over the use of the two markers separately. However, even in this case
the degree of discrimination was poor and its clinical utility was limited. In fact, to achieve a specificity of 95%, the
sensitivity of the test was about 20%; conversely, with a sensitivity of 95%, the specificity was below 10%. In conclusion,
based on our findings, we believe that blood levels of the investigated markers cannot replace bone scintigraphy in the follow-up
of breast cancer patients for the early detection of bone metastases.
Received 14 April and in revised form 5 July 1997 相似文献
84.
Ellen A. Eisen Paige E. Tolbert Marilyn F. Hallock Richard R. Monson Thomas J. Smith Susan R. Woskie 《American journal of industrial medicine》1994,26(2):185-202
A case-control study of larynx cancer was conducted within a cohort of automobile workers exposed to metal working fluids, commonly referred to as machining fluids (MF). Results are based on 108 cases of larynx cancer and 5:1 matched controls. Risks associated with specific types of MF, as well as specific components of the fluids were evaluated. Based on a retrospective exposure assessment, lifetime exposures to straight and soluble fluids, grinding particulate, biocides, selected metals, sulfur, and chlorine were examined. Exposure to asbestos and acid mists at two of the three study sites was also characterized. Results suggest that straight mineral oils are associated with almost a two-fold excess in larynx cancer risk. There was also evidence of an association with elemental sulfur, commonly added to straight MF to improve the integrity of the materials under extreme pressure and heat. It is not clear whether sulfur is causally related to an excess relative risk of larynx cancer or whether the observed association is the result of unmeasured confounding by another contaminant or process feature. For example, the high stress operations that require MF enriched with sulfur are also more likely to produce polycyclic aromatic hydrocarbons (PAHs) during the process. Thus, the observed association with sulfur may be due to an association with PAH. The finding of excess risk of laryngeal cancer associated with MF is consistent with several previous reports in the literature. This is the first study, however, to distinguish straight mineral oils from other types of MF. Based on these findings, a general reduction in concentrations of straight mineral oil particulate in occupational environments would be prudent. 相似文献
85.
自体骨髓多次注射治疗家兔骨缺损的实验研究 总被引:1,自引:0,他引:1
目的:观察骨髓多次注射的成骨性能。方法:利用家兔实验性骨缺损模型,通过大体、组织学观察,生物力学测定,评价骨髓不同移植次数促进骨缺损愈合的情况。结果:骨髓单次移植能够促进骨缺损的愈合,然而,骨髓二次移植组骨折愈合程度明显优于骨髓单次移植组,但骨髓三次移植组与骨髓二次移植组骨折愈合无明显差异。结论:在骨折愈合早期增加骨髓移植次数,能明显增强骨髓的成骨能力,加快骨折愈合 相似文献
86.
The effects of 10% dietary xylitol supplementation in ovariectomized rats were studied on the degradation of bone organic
and inorganic structures. The osseal concentrations of hydroxyproline, pyridinoline, and deoxypyridinoline were analyzed by
high-performance liquid chromatography. Bone resorption was measured in [3H]tetracycline-prelabeled rats by urinary excretion of 3H, and by the amount of 3H preserved in bone. Bone trabeculation was measured by a computer image analyzer from sections stained by the method of von
Kossa. The amount of collagen in bone organic fraction was lower in ovariectomized rats as compared with the sham-operated
controls. This most likely is partly a consequence of an increased resorption, and partly a consequence of a higher proportion
of immature periosteal bone in the ovariectomized animals, leading to a higher ratio of noncollagenous protein to collagen.
The number of pyridinium crosslinks was lower in proportion, indicating no selective changes in the structure of collagen.
Dietary xylitol significantly retarded the ovariectomy-associated decrease in the relative amount of collagen and the number
of its mature crosslinks. Ovariectomy doubled the excretion of 3H and caused a significant decrease in the amount of 3H preserved in bone; both these changes were significantly retarded by the 10% dietary xylitol supplementation. Ovariectomy
significantly decreased the volume of bone trabeculae, but this effect was also significantly inhibited by the xylitol supplementation
in the diet. In conclusion, these findings suggest a dietary xylitol-induced normalizing effect on the rate of bone turnover
in ovariectomized rats.
Received: 12 February 1996 / Accepted: 20 August 1996 相似文献
87.
Purpose: Following the widespread adoption of energy-dependent rare earth intensifying screens this study investigates the relevance of two conventions (the 10 kVp and kVp-to-the-4th-power rules) commonly used to calculate the kVp/mAs relationship.Methods: A stepwedge was exposed at standard kVp and mAs setting. The kVp was then increased in increments of 5 kVp, and appropriate mAs values were determined using a densitometer. These values were then compared with approximations from the rules previously mentioned.Results: Wide discrepancies are reported between appropriate and approximated values with the latter overestimating exposure by a factor of two.Discussion: Traditional theorems used to estimate the kVp/mAs relationship should no longer be used in modern imaging departments. Each film screen combination should be evaluated individually to ensure appropriate exposure settings. 相似文献
88.
手部创伤性骨关节缺损的处理 总被引:4,自引:0,他引:4
治疗手部骨关节缺损常采用植骨内固定、关节融合、关节成形及关节置换等方法.为总结经验,对1989年以来101例手部创伤性骨与关节缺损进行分析。单纯掌、指骨缺损39例,行直接短缩对位,克氏针内固定6例,1例发主骨不连;对33例缺损较大者用自体骨块植入克氏针交叉内固定,部分病例同时植人RBX或异体骨粒,10例发生延迟愈合,余全部正常愈合。骨与关节部分或完全缺损62例,采用关节成形术46例,其中以肋软骨移植效果最好,骨膜移植次之,筋膜衬垫或硅胶膜植入法较差;行关节融合术11例.均达顺利融合;采用自体关节置换5例,均成活,术后关节活动度均>70°。我们认为:自体骨块植入克氏针交叉内固定,必要时植入RBX骨粒.是治疗手部创伤性骨缺损的有效方法。关节缺损应按关节的重要性,分别采用关节融合术、关节成形术或关节置换术。 相似文献
89.
G. J. Breur M. D. Lapierre K. Kazmierczak K. M. Stechuchak G. P. McCabe 《Calcified tissue international》1997,61(5):418-425
In this study, we tested the hypotheses that (a) both the domain volume (volume of the cell and the matrix it has formed)
and matrix volume of juxtametaphyseal hypertrophic chondrocytes in the growth plate is tightly controlled, and that (b) the
domain volume of juxtametaphyseal hypertrophic chondrocytes is a strong determinant of the rate of bone length growth. We
analyzed the rate of bone length growth (oxytetracycline labeling techniques) and nine stereologic and kinetic parameters
related to the juxtametaphyseal chondrocytic domain in the proximal and distal radial and tibial growth plates of 21- and
35-day-old rats. The domain volume increased with increasing growth rates, independent of the location of the growth plate
and the age of the animal. Within age groups, the matrix volume per cell increased with increasing growth rates, but an identical
growth plate had the same matrix volume per cell in 21- and 35-day-old rats. The most suitable regression model (R
2= 0.992) to describe the rate of bone length growth included the mean volume of juxtametaphyseal hypertrophic chondrocytes
and the mean rate of cell loss/cell proliferation. This relationship was independent of the location of the growth plate and
the age of the animal. The data suggest that the domain volume of juxtametaphyseal hypertrophic chondrocytes, as well as the
matrix volume produced per cell, may be tightly regulated. In addition, the volume of juxtametaphyseal hypertrophic chondrocytes
and the rate of cell loss/rate of cell proliferation may play the most important role in the determination of the rate of
bone length growth.
Received: 2 December 1996 / Accepted: 24 March 1997 相似文献
90.