全文获取类型
收费全文 | 113651篇 |
免费 | 11064篇 |
国内免费 | 6257篇 |
专业分类
耳鼻咽喉 | 1093篇 |
儿科学 | 1235篇 |
妇产科学 | 1663篇 |
基础医学 | 15326篇 |
口腔科学 | 2563篇 |
临床医学 | 12711篇 |
内科学 | 19697篇 |
皮肤病学 | 1584篇 |
神经病学 | 7205篇 |
特种医学 | 3877篇 |
外国民族医学 | 58篇 |
外科学 | 13571篇 |
综合类 | 14883篇 |
现状与发展 | 20篇 |
一般理论 | 10篇 |
预防医学 | 7264篇 |
眼科学 | 3211篇 |
药学 | 11441篇 |
39篇 | |
中国医学 | 4157篇 |
肿瘤学 | 9364篇 |
出版年
2024年 | 275篇 |
2023年 | 1352篇 |
2022年 | 3018篇 |
2021年 | 3937篇 |
2020年 | 2939篇 |
2019年 | 2839篇 |
2018年 | 3315篇 |
2017年 | 2922篇 |
2016年 | 2813篇 |
2015年 | 3894篇 |
2014年 | 4921篇 |
2013年 | 4671篇 |
2012年 | 6968篇 |
2011年 | 7274篇 |
2010年 | 4325篇 |
2009年 | 3599篇 |
2008年 | 5116篇 |
2007年 | 5087篇 |
2006年 | 4919篇 |
2005年 | 4554篇 |
2004年 | 3344篇 |
2003年 | 3268篇 |
2002年 | 2851篇 |
2001年 | 5895篇 |
2000年 | 5851篇 |
1999年 | 5428篇 |
1998年 | 2329篇 |
1997年 | 1941篇 |
1996年 | 1298篇 |
1995年 | 1132篇 |
1994年 | 1082篇 |
1993年 | 801篇 |
1992年 | 2441篇 |
1991年 | 2069篇 |
1990年 | 1876篇 |
1989年 | 1781篇 |
1988年 | 1566篇 |
1987年 | 1402篇 |
1986年 | 1246篇 |
1985年 | 1054篇 |
1984年 | 668篇 |
1983年 | 509篇 |
1982年 | 284篇 |
1981年 | 215篇 |
1980年 | 155篇 |
1979年 | 315篇 |
1978年 | 92篇 |
1977年 | 75篇 |
1974年 | 81篇 |
1973年 | 101篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
目的 :提高妊娠合并柯兴氏综合征的诊治水平。方法 :结合国内外文献 16例 ,分析讨论妊娠与柯兴氏综合征的相互影响所导致的各种临床结局。结果 :肾上腺皮质腺瘤位于妊娠合并柯兴氏综合征的病因首位 ,而高肾上腺皮质激素刺激征和特征性腹部、大腿宽大紫纹 ,结合B超、CT可以诊断妊娠合并柯兴氏综合征 ;严重的并发症威胁母婴安全 ,积极进行手术治疗和并发症的处理可以降低母婴死亡率、延长孕周。结论 :妊娠合并柯兴氏综合征是极度的高危妊娠 ,妊娠期的早期诊断、早期治疗能改善妊娠质量。 相似文献
92.
目的 :对抗大肠癌细胞的单克隆噬菌体单链抗体进行初步鉴定和测序分析。方法 :采用细胞ELISA ,免疫组化 ,DNA序列测定和计算机分析方法 ,对 5个单克隆噬菌体抗体 (CH2 73,CH2 0 5 ,CH2 0 9,CHA12 ,CH72 3)进行初步鉴定和序列分析。结果 :5个抗体均对人大肠癌细胞、人胚肾上皮细胞和其它某些人肿瘤细胞反应 ,也与人正常肝细胞有弱阳性反应 ,但不与鼠源性的癌细胞和正常细胞反应。细胞免疫组化进一步证实了ELISA结果的正确性。大肠癌免疫组化对大肠癌组织有特异性的结合反应 ,而不与正常大肠组织反应。测序结果为CH2 73ScFv全长 732bp ;V ,D ,J分别属于VH3 30 D1 2 6 JH3 linker V1 13 JL2 ,GenBank序号为AY0 2 8777和AY0 2 8996 ;CH2 0 5全长 36 6bp ,V ,D ,J分别VH1 4 6 D6 13 JH3,GenBank序号为AF35 936 5 ;CH2 0 9,CHA12和CH72 3的ScFv基因完全相同 ,全长 72 3bp ,其VH DH JH与CH2 73ScFv基因中的VH DH JH 完全一致 ,V ,D ,J分别属于VH3 30 D1 2 6 JH3 linker L2 Jκ2 ,GenBank序号为AF36 3774。结论 :噬菌体抗体具有结合人大肠癌组织和细胞的活性 ,为进一步开发临床应用人源抗肿瘤抗体和小分子抗体片段奠定基础 相似文献
93.
Joseph M Dhahbi Shelley X Cao Patricia L Mote Brian C Rowley John E Wingo Stephen R Spindler 《The Journal of nutrition》2002,132(1):31-37
Molecular chaperones assist in the biosynthesis and processing of proteins. Most chaperones are induced by physiological stresses. We have shown that dietary energy restriction decreases the mRNA and protein levels of many endoplasmic reticulum chaperones in the livers of mice. Here, we have investigated the response of chaperone mRNA to feeding. Control and 50% energy-restricted C3B10RF1 mice were deprived of food for 24 h, fed, and killed 0, 1.5, 5 or 12 h after feeding. Chaperone mRNAs were strongly induced as early as 1.5 h after feeding in control and energy-restricted mice. The integrated levels of these mRNA over 24 h were significantly lower in energy-restricted mice. The mRNA response to energy intake was mirrored over the course of days in the level of chaperone protein. A similar but smaller response to feeding was found in kidney and muscle. Puromycin and cycloheximide failed to inhibit the feeding response, suggesting that feeding releases chaperone expression from an unstable inhibitor. Studies with dibutyryl-cAMP- and glucagon-supplemented, normal and streptozotocin-diabetic mice suggest that glucagon and insulin may be mediators of the feeding response. Adrenalectomy enhanced the feeding induction, but dexamethasone administration had no effect. Thus, postprandial changes in insulin and glucagon may link chaperone gene expression to feeding, possibly in several tissues including liver. 相似文献
94.
95.
J Parinaud H Grandjean M F Sarramon J M Reme X Monrozies C Sarrazin G Pontonnier 《European journal of obstetrics, gynecology, and reproductive biology》1987,24(4):285-292
In order to ascertain the adequacy of ovarian stimulation protocols with a type of follicular puncture, 126 women undergoing in vitro fertilization received either combination clomiphene/hMG or hMG alone according to a randomized test protocol. Within both groups patients for whom a pelvic examination was required had laparoscopies, while others had transvaginal ultrasonically guided punctures as far as possible. Clomiphene/hMG was more efficient than hMG alone as assessed from the cleavage rate (68% vs. 54%; p less than 0.01) and the pregnancy per attempt rate (16% vs. 5%; p less than 0.05). Laparoscopic punctures were more efficient than ultrasonically guided punctures (mean number of recovered oocytes: 4.8 +/- 2.6 vs. 3 +/- 2.5; p less than 0.001), but slightly better results were achieved by this latter method in ongoing pregnancy per puncture rate (18% vs. 8%; NS). With ultrasonically guided punctures, stimulation by clomiphene/hMG allowed better oocyte recoveries (3.8 +/- 2.5 vs. 2.3 +/- 1.9, p less than 0.05). Such results constitute an argument for preferential use of the clomiphene/hMG stimulation protocol with ultrasonically guided punctures. 相似文献
96.
目的 探讨种植受体血管内皮细胞在抗异种血管移植超急排斥反应 (HAR)方面的意义。方法 选用豚鼠→大鼠移植模型 ,先将分离、培养的大鼠动脉内皮细胞种植于去内皮的豚鼠动脉内壁 ,再将此豚鼠动脉植入大鼠体内 ,观察动脉血栓形成时间 ,并采用免疫组化技术检测了 Ig M、C3在移植后豚鼠动脉壁上沉积的情况。结果 已种植大鼠内皮细胞的豚鼠动脉血栓形成时间 (2 0 .3± 4.42 h)较植入大鼠体内的正常豚鼠动脉 (0 .35± 0 .2 84h)以及单纯去内皮豚鼠动脉血栓形成时间 (0 .16 5± 0 .0 77h)显著延长 (P<0 .0 0 1)。免疫组化结果显示 ,植入大鼠体内的正常豚鼠内皮细胞表面有 Ig M和 C3沉积 ,而预先种植大鼠内皮细胞的豚鼠动脉内壁无 Ig M和 C3沉积。结论 在异种供体血管壁上预先种植受者血管内皮细胞 ,可延长移植的异种供体血管通畅时间 ,该技术可能在抗异种血管移植 HAR方面具有重要意义 相似文献
97.
Campylobacter jejuni cultured in a candle jar 总被引:3,自引:0,他引:3
98.
The effects of intracellular Ca2+ (Ca2+i) on K+ currents in hippocampal cells were examined using acutely isolated cells obtained from adult guinea pigs. Whole-cell voltage-clamp recordings were carried out in a configuration that allowed a continuous perfusion of the intracellular medium. Recording media were made to block inward currents and allowed selective activation of K(+)-dependent outward currents. Voltage-dependent outward currents consisted of an initial rapidly decaying component followed by a sustained component. The time constant of decay of the transient current was about 25 msec, and previous studies (Numann et al., 1987) showed that the kinetic and pharmacological properties of this current closely resembled the A current recorded in invertebrate neurons (Connor and Stevens, 1971; Thompson, 1982). Intracellular perfusion of hippocampal cells with a solution containing elevated Ca2+ (about 4.5 x 10(-4) M) elicited outward currents at the holding potential (-45 to -55 mV) and produced changes in voltage-dependent K+ currents. The transient outward current (IA) activated by depolarization was suppressed with increases in Ca2+i. Delayed, sustained K+ currents were greatly potentiated. Data also showed that, among the 3 effects elicited by Ca2+i, suppression of IA was most sensitive to Ca2+i elevation. Previous results (Numann et al., 1987) showed that IA had a lower threshold (about -45 mV) than sustained currents (about -40 mV). By using low levels of depolarization (-40 mV), IA can be selectively activated, and the suppressive effect of Ca2+i on IA was confirmed on the kinetically isolated IA.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
99.
Sherry X Yang Richard M Simon Antoinette R Tan Diana Nguyen Sandra M Swain 《Clinical cancer research》2005,11(17):6226-6232
PURPOSE: To delineate gene expression patterns and profile changes in metastatic tumor biopsies at baseline and 1 month after treatment with the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor erlotinib in patients with metastatic breast cancer. EXPERIMENTAL DESIGN: Patients were treated with 150 mg of oral erlotinib daily. Gene expression profiles were measured with Affymetrix U133A GeneChip and immunohistochemistry was used to validate microarray findings. RESULTS: Estrogen receptor (ER) status by immunohistochemistry is nearly coincided with the two major expression clusters determined by expression of genes using unsupervised hierarchical clustering analysis. One of 10 patients had an EGFR-positive tumor detected by both microarray and immunohistochemistry. In this tumor, tissue inhibitor of metalloproteinases-3 and collagen type 1 alpha 2, which are the EGF-down-regulated growth repressors, were significantly increased by erlotinib. Gene changes in EGFR-negative tumors are those of G-protein-linked and cell surface receptor-linked signaling. Gene ontology comparison analysis pretreatment and posttreatment in EGFR-negative tumors revealed biological process categories that have more genes differentially expressed than expected by chance. Among 495 gene ontology categories, the significant differed gene ontology groups include G-protein-coupled receptor protein signaling (34 genes, P = 0.002) and cell surface receptor-linked signal transduction (74 genes, P = 0.007). CONCLUSIONS: ER status reflects the major difference in gene expression pattern in metastatic breast cancer. Erlotinib had effects on genes of EGFR signaling pathway in the EGFR-positive tumor and on gene ontology biological process categories or genes that have function in signal transduction in EGFR-negative tumors. 相似文献
100.
Persistent reversal of diabetes by transplantation of fetal pig proislets into nude mice 总被引:3,自引:0,他引:3
Facing the limited availability of human adult and fetal pancreases, fetal pig proislets (pancreatic islet precursors) were investigated in view of several inherent advantages. Six litters of fetuses of mean +/- SE gestational age 75 +/- 3 days were obtained from commercially available farm pigs. Pancreatic tissue was gently digested with collagenase, then a 10-day culture was performed. During culture, fetal proislets showed no insulin response to glucose alone but a significant response to glucose plus theophylline. The insulin content per microgram of DNA in the cultured proislets continuously increased. Histological examination by immunoperoxidase staining showed that, apart from single insulin- and glucagon-positive cells, there were no discrete islets in the pancreatic tissue and the cultured proislets. Diabetes was induced with streptozocin (STZ) in eight nude mice 3-4 wk after proislet transplantation and in another eight nude mice without transplantation. During the initial week, blood glucose levels of mice in both groups increased rapidly. The mean +/- SE peak value of blood glucose levels in the transplanted group was 20.4 +/- 2.0 mM and was 20.1 +/- 1.3 mM in the group without transplantation. Simultaneously, body weight decreased from 29.5 +/- 0.7 to 21.5 +/- 0.9 g and from 27.9 +/- 0.7 to 19 +/- 1 g in the groups, respectively. Afterward, blood glucose levels of mice in the transplanted group gradually decreased, and normoglycemia was achieved in all mice within 50 +/- 13 days after injection of STZ, i.e., 74 +/- 13 days after transplantation. The group without transplantation persistently maintained blood glucose levels greater than 16.7 mM.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献