全文获取类型
收费全文 | 7064篇 |
免费 | 358篇 |
国内免费 | 53篇 |
专业分类
耳鼻咽喉 | 59篇 |
儿科学 | 87篇 |
妇产科学 | 70篇 |
基础医学 | 1077篇 |
口腔科学 | 172篇 |
临床医学 | 497篇 |
内科学 | 1930篇 |
皮肤病学 | 27篇 |
神经病学 | 700篇 |
特种医学 | 251篇 |
外科学 | 1026篇 |
综合类 | 33篇 |
预防医学 | 127篇 |
眼科学 | 138篇 |
药学 | 525篇 |
中国医学 | 20篇 |
肿瘤学 | 736篇 |
出版年
2023年 | 35篇 |
2022年 | 61篇 |
2021年 | 161篇 |
2020年 | 70篇 |
2019年 | 102篇 |
2018年 | 133篇 |
2017年 | 108篇 |
2016年 | 141篇 |
2015年 | 154篇 |
2014年 | 181篇 |
2013年 | 273篇 |
2012年 | 388篇 |
2011年 | 459篇 |
2010年 | 271篇 |
2009年 | 230篇 |
2008年 | 419篇 |
2007年 | 464篇 |
2006年 | 475篇 |
2005年 | 404篇 |
2004年 | 421篇 |
2003年 | 435篇 |
2002年 | 420篇 |
2001年 | 102篇 |
2000年 | 95篇 |
1999年 | 124篇 |
1998年 | 121篇 |
1997年 | 108篇 |
1996年 | 91篇 |
1995年 | 68篇 |
1994年 | 92篇 |
1993年 | 68篇 |
1992年 | 76篇 |
1991年 | 82篇 |
1990年 | 64篇 |
1989年 | 50篇 |
1988年 | 60篇 |
1987年 | 33篇 |
1986年 | 52篇 |
1985年 | 51篇 |
1984年 | 46篇 |
1983年 | 34篇 |
1982年 | 20篇 |
1981年 | 26篇 |
1980年 | 25篇 |
1979年 | 23篇 |
1978年 | 20篇 |
1977年 | 16篇 |
1972年 | 17篇 |
1971年 | 14篇 |
1968年 | 14篇 |
排序方式: 共有7475条查询结果,搜索用时 15 毫秒
51.
A histological evaluation for guided bone regeneration induced by a collagenous membrane 总被引:5,自引:0,他引:5
Taguchi Y Amizuka N Nakadate M Ohnishi H Fujii N Oda K Nomura S Maeda T 《Biomaterials》2005,26(31):6158-6166
This study was designed to evaluate the histological changes during ossification and cellular events including osteogenic differentiation responding to collagenous bioresorbable membranes utilized for GBR. Standardized artificial bony defects were prepared at rat maxillae, and covered with a collagenous bioresorbable membrane. These animals were sacrificed at 1, 2, 3 and 4 weeks after the GBR-operation. The paraffin sections were subject to tartrate resistant acid phosphatase (TRAP) enzyme histochemistry and immunohistochemistry for alkaline phosphatase (ALP), osteopontin (OP) and osteocalcin (OC). In the first week of the experimental group, woven bone with ALP-positive osteoblasts occupied the lower half of the cavity. The collagenous membrane included numerous ALP-negative cells and OP-immunoreactive extracellular matrices. At 2 weeks, the ALP-, OP- and OC-immunoreactivity came to be recognizable in the region of collagenous membrane. Since ALP-negative soft tissue separated the collagenous membrane and the new bone originating from the cavity bottom, the collagenous membrane appeared to induce osteogenesis in situ. At 3 weeks, numerous collagen fibers of the membrane were embedded in the adjacent bone matrix. At 4 weeks, the membrane-associated and the cavity-derived bones had completely integrated, showing the same height of the periosteal ridge as the surrounding alveolar bones. The collagen fibers of a GBR-membrane appear to participate in osteogenic differentiation. 相似文献
52.
Kawashita M Shineha R Kim HM Kokubo T Inoue Y Araki N Nagata Y Hiraoka M Sawada Y 《Biomaterials》2003,24(17):2955-2963
Radiotherapy is one of the most effective treatments for cancers. However, external irradiation provides only small doses to deep-seated cancers, and often causes damage to healthy tissues. It has been reported that 20-30 microm diameter 17Y(2)O(3)-19Al(2)O(3)-64SiO(2) (mol%) glass microspheres are useful for the in situ irradiation of cancers. Yttrium-89 (89Y) in this glass can be neutron bombarded to form the beta-emitter 90Y (half-life=64.1h). When injected in the vicinity of the cancer, such activated glass microspheres can provide a large localized dose of beta-radiation. The Y(2)O(3) content of the glass in the microspheres is limited to only 17 mol%. Chemically durable microspheres with a higher Y(2)O(3) content need to be developed. Phosphorus-31 (31P) with 100% natural abundance can also be activated by neutron bombardment to form the beta-emitter 32P (half-life=14.3d). Chemically durable microspheres containing a high phosphorus content are expected to be more effective for cancer treatment. We prepared pure Y(2)O(3) and YPO(4) microspheres using a high-frequency induction thermal plasma melting technique, and investigated the resulting structure and chemical durability. We successfully prepared smooth, highly spherical polycrystalline Y(2)O(3) and YPO(4) microspheres with diameters in the range 20-30 microm. Both the Y(2)O(3) and YPO(4) microspheres showed high chemical durability in saline solutions buffered at pH=6 and 7. These microspheres are expected to be more effective than the conventional glass microspheres for the in situ radiotherapy of cancer. 相似文献
53.
Intracellular staining with HRP of physiologically identified group Ia and Ib afferent fibers in the adult cat lumbosacral cord revealed that group Ia and Ib fibers take a similar course in the dorsal funiculus, but the collaterals emerging from them show a different topographical distribution and a different mode of branching in the gray matter. Ia collaterals terminate in laminae VI, VII, IX, and sometimes VIII, whereas Ib collaterals terminate only in lamina VI, or both VI and IX. In lamina IX, two large motor-type neurons received terminations of both Ia and Ib fibers at the same time. 相似文献
54.
Norio Kunieda Akira Suzuki Masayoshi Kinoshita Minoru Imoto 《Macromolecular chemistry and physics.》1972,152(1):35-42
Kinetic studies on the acid-catalyzed reaction of formaldehyde with diphenyl sulfide (DPS) were carried out in acetic acid in the presence of sulfuric acid. The rate of the initial stage of the reaction was found to be in agreement with the following equation. The relative rates of diphenyl sulfide and its homologous compounds in the reaction with formaldehyde gave a good correlation with BROWN -OKAMOTO 's σ⊕ values and a large ρ value. The polar effects of substituents of the substituted diphenyl sulfides on the rates were found to be considerably large. From these results a plausible mechanism of the reaction has been deduced. 相似文献
55.
Isolation and radiation hybrid mapping of a dinucleotide repeat polymorphism at the human calcium-sensing receptor (CASR) locus 总被引:2,自引:0,他引:2
Kazuhiro Tsukamoto Ikuyo Watanabe Tadayoshi Shiba M. Emi 《Journal of human genetics》1998,43(4):280-282
Calcium-sensing receptor (CASR) in parathyroid gland regulates calcium homeostasis by sensing decreases in extracellular
calcium levels and effecting an increase in secretion of parathyroid hormone. A polymorphic dinucleotide (CA) sequence was
isolated from a genomic clone containing the human CASR gene and was mapped to 3q13.3–q21. This polymorphism will be useful in the genetic study of disorders affecting calcium metabolism,
such as hypercalcemia, hypocalcemia, osteoporosis, hyperparathyroidism, and hypoparathyroidism.
Received: June 2, 1998 / Accepted: June 24, 1998 相似文献
56.
Satoshi Fujishita Noritoshi Shibuya Norio Niikawa Shigenobu Nagataki 《Journal of human genetics》1991,36(4):317-324
Polymerase chain reaction (PCR)-based diagnosis was carried out in 62 patients (57 probands) with Duchenne or Becker muscular dystrophy (DMD or BMD) and 226 members in 57 families. The PCR studies were also performed for carrier detection in 57 mothers and 58 sisters, and prenatal diagnosis of 4 fetuses at risk of DMD. The PCR with 7 sets of primers, which amplify 7 different exon-sequences of the dystrophin gene, detected gene deletion of at least one exon in 49% of the probands. The PCR with the other 4 primer sets, which amplify 3 intragenic loci, and subsequent endonuclease digestion detected in 84% of the mothers a heterozygous pattern in at least one such locus/segment. Using the same primer sets, carrier detection was successful in 5 sisters of familial DMD cases, while recombination between the ERT87 and the 3 end intragenic loci was observed in 11% of family members studied. Prenatal diagnosis was made in all the 4 fetuses; two males were affected, one male fetus non-affected, and the remaining one female fetus a carrier. Thus, the PCR study and the primers used in the present study are useful and convincing for rapid diagnosis of DMD and/or BMD. 相似文献
57.
Han-Xiang Deng Jia-Hui Xia Mutsuo Ishikawa Norio Niikawa 《Journal of human genetics》1990,35(3):245-251
Parental origin and mechanism of formation of X chromosome structural anbormalities were studied in one each case of dup(X)(pter p11.4::p22.1qter), del(X)(qterp11:), i(X)(qtercenqter), and inv dup(X) (pterq22::q22pter) using various X-linked RFLPs as genetic markers. Segregation and densitometric analyses on polymorphic DNAs revealed that the dup(Xp) and the del(Xp) are both of paternal origin and the i(Xq) and i dic(X) are of maternal origin. The dup(Xp) had arisen by an unequal sister chromatid exchange and the del(Xp) had occurred through an intrachromosomal breakage-reunion mechanism, both in the paternal X chromosome. The i(Xq) had arisen either through centromere fission of a maternal X chromosome, followed by duplication, of its long-arm, or through a translocation between two maternal X chromosomes after meiotic crossing-over. The inv dup(X) arose through sister chromatid breakage and reunion in a maternal X chromosome. These results, together with those of previous studies, suggest that thede novo abnormalities due to events involving centromere disruption arise predominantly during oogenesis, while those due to simple breakage-reunion events occur preferentially during spermatogenesis. 相似文献
58.
K. Haukipuro N. Keränen E. Koivisto R. Lindholm R. Norio L. Punto 《Clinical genetics》1978,13(6):471-476
In a Finnish kindred consisting of 192 descendants from two marriages of a male ancestor born in 1868, the lumbar spines of 105 of the 170 living members were X-rayed. Spondylolysis was found in 22 individuals. In addition, six of them had spondylolisthesis, four had spina bifida occulta, and two had a transitional lumbar/sacral vertebra. Seven members of the kindred without spondylolysis had spina bifida occulta and 10 had transitional lumbar vertebrae.
The pedigree is consistent with autosomal dominant inheritance and incomplete (about 75 %) penetrance for spondylolysis. It raises the question of a common aetiology for several congenital disturbances in the formation of lumbar vertebrae and possibly supports the concept of a variable expressivity of a "spondylolysis gene". 相似文献
The pedigree is consistent with autosomal dominant inheritance and incomplete (about 75 %) penetrance for spondylolysis. It raises the question of a common aetiology for several congenital disturbances in the formation of lumbar vertebrae and possibly supports the concept of a variable expressivity of a "spondylolysis gene". 相似文献
59.
60.
Yokomizoi K Nakayama A Hokazono E Ninomiya A Miyake R Hiratsuka N Okuyama M Kato Y Kobayashi S Ito Y Shiba K 《Rinsho byori. The Japanese journal of clinical pathology》2005,53(12):1109-1115
In order to investigate the mechanism of urinary tract stone formation, we analyzed protein components in urine and the stone. Urinary proteins of healthy subjects and urolithic patients as well as protein components urinary tract stone of the urolithic patients were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Electrophoretic patterns of urinary proteins of the patients differed from those of healthy subjects after separating protein patterns into those larger than 66kDa or smaller than 30kDa. Protein constituents of urinary tract stone were mainly separated into 18 bands ranging from 26.8 to 143 kDa. Major bands among these 18 bands differed among stones from different patients. On western blotting, the developed intensities of Tamm-Horsfall protein (THP) were fainter than those of healthy subjects. Whereas intensities of albumin (ALB) were stronger than those of healthy subjects. Moreover, blotting patterns of THP of the patients on non-reducing SDS-PAGE were obviously broad. Thus, we suggest that analysis of fractionated urinary proteins or protein components of urinary tract stone may provide a tool for monitoring the prognosis or relapse in the patients. 相似文献