全文获取类型
收费全文 | 6101篇 |
免费 | 283篇 |
国内免费 | 49篇 |
专业分类
耳鼻咽喉 | 40篇 |
儿科学 | 85篇 |
妇产科学 | 58篇 |
基础医学 | 977篇 |
口腔科学 | 73篇 |
临床医学 | 389篇 |
内科学 | 1681篇 |
皮肤病学 | 17篇 |
神经病学 | 695篇 |
特种医学 | 195篇 |
外科学 | 860篇 |
综合类 | 27篇 |
预防医学 | 104篇 |
眼科学 | 98篇 |
药学 | 446篇 |
中国医学 | 21篇 |
肿瘤学 | 667篇 |
出版年
2023年 | 25篇 |
2022年 | 32篇 |
2021年 | 141篇 |
2020年 | 56篇 |
2019年 | 87篇 |
2018年 | 113篇 |
2017年 | 83篇 |
2016年 | 119篇 |
2015年 | 130篇 |
2014年 | 160篇 |
2013年 | 236篇 |
2012年 | 351篇 |
2011年 | 411篇 |
2010年 | 256篇 |
2009年 | 207篇 |
2008年 | 379篇 |
2007年 | 415篇 |
2006年 | 427篇 |
2005年 | 366篇 |
2004年 | 376篇 |
2003年 | 389篇 |
2002年 | 395篇 |
2001年 | 73篇 |
2000年 | 64篇 |
1999年 | 98篇 |
1998年 | 110篇 |
1997年 | 94篇 |
1996年 | 86篇 |
1995年 | 63篇 |
1994年 | 91篇 |
1993年 | 67篇 |
1992年 | 64篇 |
1991年 | 68篇 |
1990年 | 36篇 |
1989年 | 49篇 |
1988年 | 36篇 |
1987年 | 31篇 |
1986年 | 39篇 |
1985年 | 39篇 |
1984年 | 33篇 |
1983年 | 16篇 |
1982年 | 15篇 |
1981年 | 17篇 |
1980年 | 19篇 |
1979年 | 8篇 |
1978年 | 14篇 |
1977年 | 7篇 |
1976年 | 8篇 |
1975年 | 8篇 |
1974年 | 6篇 |
排序方式: 共有6433条查询结果,搜索用时 31 毫秒
61.
Yamamoto N Yang M Jiang P Xu M Tsuchiya H Tomita K Moossa AR Hoffman RM 《Clinical & experimental metastasis》2003,20(7):633-638
We have established stable, bright green fluorescent protein (GFP)- or red fluorescent protein (RFP)-expressing HT-1080 human
fibrosarcoma clones. These cell lines showed similar cell proliferation rates and high-frequency experimental lung metastasis.
The HT-1080-GFP and -RFP clones enable simultaneous real-time dual-color imaging in the live animal. HT-1080 cells were transduced
with retroviral vectors containing GFP or RFP and the neomycin resistance gene. Stable transformants were selected stepwise
with G418 up to 800 μl/ml. Subsequently, high GFP- or RFP-expressing clones, HT-1080-GFP or HT-1080-RFP, respectively, were
selected. 3×106 cells from each clone were mixed and injected into the tail vein of SCID mice. The cells seeded the lung at high frequency
with subsequent formation of pure green and pure red colonies as well as mixed yellow colonies with different patterns visualized
directly on excised lungs. The lung metastases were also visualized by external fluorescence imaging in live animals through
skin-flap windows over the chest wall. Lung metastases were observed on the lung surface of all mice. SCID mice well tolerated
multiple surgical procedures for direct-view imaging via skin-flap windows. Real-time metastatic growth of the two different
colored clones in the same lung was externally imaged with resolution and quantification of green, red, or yellow colonies
in live animals. The color coding enabled determination of whether the colonies grew clonally or were seeded as a mixture
with one cell type eventually dominating, or whether the colonies grew as a mixture. The simultaneous real-time dual-color
imaging of metastatic colonies described in this report gives rise to the possibility of color-coded imaging of clones of
cancer cells carrying various forms of gene of interest.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
62.
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
63.
YMDD mutants in patients with chronic hepatitis B before treatment are not selected by lamivudine 总被引:2,自引:0,他引:2
64.
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
65.
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
66.
67.
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
68.
Norio Fukuda Hideaki Fujita Takashi Fujita Shin’ichi Ishiwata 《Pflügers Archiv : European journal of physiology》1996,433(1-2):1-8
Skinned fibres from bovine ventricles exhibited spontaneous tension oscillations when MgADP and inorganic phosphate (Pi)
were added to the solution bathing fibres in the relaxed state (ADP-SPOC). A similar type of oscillation was observed at intermediate
concentrations of free Ca2+ in the absence of MgADP and Pi (Ca-SPOC). To investigate the correlation between ADP-SPOC and Ca-SPOC, we constructed two-dimensional
state diagrams of cardiac muscle using different concentrations of Pi (0–20 mM) and free Ca2+ [pCa=around 5 (+Ca2+), pCa=5.15–6.9 and +EGTA (–Ca2+)], with varying concentrations of MgADP (0–10 mM), with 2 mM MgATP and 2 mM free Mg2+ maintaining ionic strength at 0.15±0.01 M, pH 7.0, 25 °C. The three-dimensional (pCa-Pi-MgADP) state diagram thus obtained
was divided into three regions, i.e. the contraction region in which tension oscillation was undetectable, the spontaneous
tension oscillation (SPOC) region and the relaxation region. We found that the regions of ADP-SPOC and Ca-SPOC were continuously
connected by a single oscillation region sandwiched between the contraction and relaxation regions. The state diagram, which
encompasses physiological conditions, shows that the probability of SPOC is higher in cardiac muscle than in skeletal muscle.
From these results, we suggest that, despite distinct ionic conditions, the molecular state of cross-bridges during SPOC is
common to both ADP-SPOC and Ca-SPOC.
Received 19 February 1996 / Received after revision: 16 July 1996 / Accepted: 14 August 1996 相似文献
69.
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
70.
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