全文获取类型
收费全文 | 32194篇 |
免费 | 1611篇 |
国内免费 | 166篇 |
专业分类
耳鼻咽喉 | 380篇 |
儿科学 | 588篇 |
妇产科学 | 305篇 |
基础医学 | 4060篇 |
口腔科学 | 892篇 |
临床医学 | 2275篇 |
内科学 | 7889篇 |
皮肤病学 | 585篇 |
神经病学 | 2516篇 |
特种医学 | 1283篇 |
外科学 | 5206篇 |
综合类 | 202篇 |
预防医学 | 1174篇 |
眼科学 | 475篇 |
药学 | 2743篇 |
中国医学 | 70篇 |
肿瘤学 | 3328篇 |
出版年
2022年 | 311篇 |
2021年 | 556篇 |
2020年 | 262篇 |
2019年 | 398篇 |
2018年 | 518篇 |
2017年 | 419篇 |
2016年 | 499篇 |
2015年 | 537篇 |
2014年 | 707篇 |
2013年 | 887篇 |
2012年 | 1299篇 |
2011年 | 1392篇 |
2010年 | 801篇 |
2009年 | 706篇 |
2008年 | 1242篇 |
2007年 | 1295篇 |
2006年 | 1330篇 |
2005年 | 1412篇 |
2004年 | 1339篇 |
2003年 | 1308篇 |
2002年 | 1367篇 |
2001年 | 1239篇 |
2000年 | 1387篇 |
1999年 | 1216篇 |
1998年 | 419篇 |
1997年 | 316篇 |
1996年 | 327篇 |
1995年 | 275篇 |
1994年 | 266篇 |
1993年 | 252篇 |
1992年 | 828篇 |
1991年 | 754篇 |
1990年 | 769篇 |
1989年 | 800篇 |
1988年 | 727篇 |
1987年 | 649篇 |
1986年 | 619篇 |
1985年 | 593篇 |
1984年 | 449篇 |
1983年 | 333篇 |
1982年 | 190篇 |
1980年 | 162篇 |
1979年 | 292篇 |
1978年 | 228篇 |
1977年 | 176篇 |
1974年 | 178篇 |
1973年 | 164篇 |
1971年 | 163篇 |
1969年 | 176篇 |
1968年 | 158篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
We have successfully applied a reverse flow island flap of extensor digitorum brevis muscle for coverage of tissue defects in the distal portion of the foot dorsum in 2 patients. This flap covered the metatarsophalangeal area well with cadaver limb dissection and seems useful to cover the defect in the distal foot dorsum. 相似文献
102.
Restricted diversity of the variable region nucleotide sequences of the heavy and light chains of a human rheumatoid factor 总被引:6,自引:0,他引:6
I Ezaki H Kanda K Sakai N Fukui M Shingu M Nobunaga T Watanabe 《Arthritis and rheumatism》1991,34(3):343-350
The complete nucleotide sequences of the variable region genes of the heavy and light polypeptide chains of a human monoclonal rheumatoid factor (RF) produced from a human-mouse heterohybridoma were determined. The antibody, designated YES8c, contained V kappa III, J kappa 2, VH1, JH4, and a D gene segment of 9 amino acids. The nucleotide sequences and the deduced amino acid sequences of the light chain variable region were remarkably homologous (97-98%) to previously described RF of the Wa idiotypic family (PAY, GLO, CUR, FLO, and GAR) and to that of a V kappa III germline gene (Humkv325). The YES8c heavy chain variable region gene was most closely related to the VH1 gene of the restricted human fetal repertoire, designated 51p1, and also to 3 rearranged VH1 genes that were recently isolated from patients with chronic lymphocytic leukemia. These results suggest that variable region genes of RFs are highly conserved and that YES8c VH, as well as V kappa, may be identical to heavy and light chains expressed during early B cell development. 相似文献
103.
104.
K Matsumoto Y Asano J Saitou K Kaneko T Yamamoto M Uchida T Tamura C Suga Y Dohi H Watanabe 《呼吸と循環》1992,40(10):999-1002
To apply Nd:YAG laser irradiation through a new sapphire tip contact laser method to catheter ablation in treatment of tachy-arrhythmias, effects of laser irradiation on ventricular myocardium were investigated in 10 mongrel dogs. Nd:YAG lase (1064nm) discharges were delivered to different sites on the endomyocardium at power of 5, 10, 15, 20 or 25w with duration of 3, 5, or 10 seconds (sec.) respectively in closed beating hearts. Histopathologically, the lesion irradiated was clearly demarcated from the normal myocardium by the construction band necrosis zone. The depth of injured myocardium was less than 2mm with 3 sec. irradiations, with 5 sec. from 1 mm to 4 mm in proportion to power increase, with 10 sec. from 3mm to 8 mm in proportion to the power from 5w to 15w and could not be measured in cases of more than 20w irradiations. Although with every irradiation duration, the depth of injury increased in proportion to the power increase. With the same total energy, a longer time of irradiation produced deeper injury than a shorter time. This method makes it easier to keep the laser positioned to target than bare laser, and is suitable for use in catheter ablation. 相似文献
105.
M N Hosono K Endo H Sakahara Y Watanabe T Saga T Nakai M Hosono T Nakajima Y Onoyama J Konishi 《Cancer》1992,70(12):2851-2856
BACKGROUND. CA 125 is a representative ovarian cancer-associated antigen defined by monoclonal antibody OC125. Recently, monoclonal antibodies were produced (designated 130-22 and 145-9) that were reactive with CA 125 but bound to a separate epitope named CA 130. There was a close correlation between serum CA 125 and CA 130 values in most instances. However, among more than 8000 serum samples, 5 apparently normal women had high serum CA 125 values, despite having normal CA 130 values. In this study, the antigenic nature of these five women was investigated. METHODS. Using gel chromatography, the molecular masses of CA 125 and CA 130 were estimated that were found in the five women with false-positive CA 125 values. The sera were examined using double-determinant assays combining iodine-125-labeled OC125 or iodine-125-labeled 130-22 with OCI25-coated or 145-9-coated beads. RESULTS. The molecular masses of both CA 125 and CA 130 were estimated as greater than 1000 kilodaltons (KD); the CA 130 mass from one of the five women with an abnormal CA 125 level was approximately 200 KD using gel chromatography. Using the double-determinant assays that combined iodine-125-labeled OC125 or iodine-125-labeled 130-22 with OC125-coated or 145-9-coated beads, high radioactivity was found only in the homologous assay using iodine-125-labeled OC125 with OC125-coated beads. These results suggest that the antigenic nature of CA 125 found in apparently healthy women differs from that found in patients with ovarian cancer and that CA 130 epitopes are not present. CONCLUSIONS. Measurement of serum CA 130 concentrations may be useful for excluding women with falsely elevated CA 125 values. 相似文献
106.
Kazuki Tamura Tadayuki Oka Kazutaka Ohsawa Takehiko Koji Yoji Watanabe Shigeru Katamine Hiroshi Sato Hiroyoshi Ayabe 《The Journal of heart and lung transplantation》2003,22(4):452-459
BACKGROUND: Cytomegalovirus (CMV) diseases commonly occur in allograft recipients in the early post-transplant period. However, factors responsible for the high incidence of CMV diseases during this period are not yet fully defined. METHODS: Wistar-Furth (WF; RT-1(u)) rats were inoculated with 10(4) plaque-forming units (PFU) of rat CMV (RCMV) intraperitoneally, and then transplanted with allogeneic lungs from Dark Agouti (DA; RT-1avl) rats or stimulated with 10(7) mitomycin C-treated spleen cells from DA rats by daily sub-cutaneous injections for 2 weeks. No immunosuppressive agent was used. Naive WF rats and WF rats grafted with syngeneic lungs or cells were used as controls. The level of RCMV replication in rats was assessed by infectious virus titers in tissues. RESULTS: The virus titers in salivary glands of allogeneic and syngeneic lung graft recipients were significantly higher than in naive WF rats. The level of RCMV replication in rats stimulated with allogeneic spleen cells was significantly higher than in the syngeneic recipient rats: virus titers in the salivary gland of allogeneic and syngeneic recipients reached 4.61 +/- 0.33 and 4.00 +/- 0.37 log(10) PFU/g tissue, respectively, at 14 days post-infection (p = 0.015). The augmented viral replication in allogeneic recipients was confirmed by an increase in the number of RCMV antigen-positive macrophages present in tissue sections of the salivary gland. CONCLUSIONS: Acute lung allograft rejection and allogeneic spleen cell stimulation enhance CMV replication in the salivary gland of rats. Various responses to allogeneic antigens occurring in the process of acute allograft rejection could be risk factors for post-transplant CMV replication and infection. 相似文献
107.
Yoichi Sato Hitoshi Yokoyama Masaaki Watanabe Osami Hamada 《Annals of thoracic and cardiovascular surgery》2003,9(6):401-405
A 74-year-old man with combined valvular disease with a recent cerebral infarction was admitted. While undergoing thorough examination for valvular disease, absent right superior vena cava (RSVC) and persistent left superior vena cava (PLSVC) were recognized. Chest X-ray film suggested a right arch protrusion, and CT and venogram confirmed the diagnosis. During surgery, replacement of the mitral and aortic valves and annuloplasty of the tricuspid valve were performed. A blood draining cannula was inserted in retrograde fashion from the coronary sinus into the PLSVC, without any difficulties in the tricuspid valve repair. Due to bradycardic atrial fibrillation, we believed that it would be difficult to insert an endocardial electrode postoperatively, hence myocardial electrode was placed in the right ventricular wall. Absent RSVC combined with PLSVC is very rare, and a patient who underwent combined valve surgery with this rare anatomical abnormality is herein presented. 相似文献
108.
Endogenous tumor necrosis factor exerts its protective function intracellularly against the cytotoxicity of exogenous tumor necrosis factor. 总被引:5,自引:0,他引:5
T Okamoto N Watanabe N Yamauchi Y Tsuji N Tsuji Y Itoh H Neda Y Niitsu 《Cancer research》1992,52(19):5278-5281
Based on the findings that expression of endogenous tumor necrosis factor (enTNF), which is not present in TNF-susceptible cells, was generally observed in TNF-resistant cells and that TNF gene transfection gives rise to TNF resistance, the assumption was made that enTNF may be a protective protein against the cytotoxicity of exogenous TNF. However, it remains unknown whether the protection by enTNF is exerted in an intracellular or extracellular (autocrine) manner. We therefore transfected a nonsecretory human TNF gene (pTNF delta pro) into highly TNF-sensitive mouse tumorigenic fibroblasts (L-M cells) and investigated their TNF susceptibility. The transfectants expressed enTNF which was not secreted into the medium and acquired an appreciable degree of resistance to exogenous TNF. A significant increase in the manganous superoxide dismutase level was also noted in the transfectants. These findings suggest that enTNF exerts its protective function intracellularly by inducing manganous superoxide dismutase production. 相似文献
109.
Endogenous tumor necrosis factor functions as a resistant factor against hyperthermic cytotoxicity. 总被引:4,自引:0,他引:4
Y Tsuji N Watanabe T Okamoto N Tsuji H Sasaki S Akiyama N Yamauchi Y Niitsu 《Cancer research》1992,52(22):6258-6262
One of the mechanisms of cytotoxicity by tumor necrosis factor (TNF) is the induction of reactive oxygen molecules. Cells producing endogenous tumor necrosis factor (enTNF) show resistance to the cytotoxicity of exogenous TNF by scavenging the reactive oxygen molecules. The intracellular hydroxyl radical production is also known to be involved in the heat-induced cytotoxicity. In the present study, we therefore examined the possibility that enTNF may act as a protective protein against the heat-induced cytotoxicity in a manner similar to that of exogenous TNF. Heat-sensitive L-M (mouse tumorigenic fibroblast) cells, originally expressing no enTNF, were transfected with a human TNF expression vector to produce enTNF. The stable transfectants showed apparent resistance to heat treatment. Conversely, when HeLa (human uterine cervical cancer) cells, originally producing an appreciable amount of enTNF, were transfected with an antisense TNF mRNA expression vector to inhibit enTNF synthesis, their heat sensitivity was enhanced. Furthermore, L-M cells which were transfected with nonsecretory human TNF expression vector also acquired resistance to heat treatment. In these cells, heat resistance correlated well with expression of enTNF and intracellular levels of manganous superoxide dismutase. These results indicate that enTNF exerts its intracellular protective effect against the heat-induced cytotoxicity by scavenging reactive oxygen with induced manganous superoxide dismutase in a manner similar to that found in cells treated with exogenous TNF. 相似文献
110.