全文获取类型
收费全文 | 19471篇 |
免费 | 1232篇 |
国内免费 | 40篇 |
专业分类
耳鼻咽喉 | 231篇 |
儿科学 | 528篇 |
妇产科学 | 326篇 |
基础医学 | 2813篇 |
口腔科学 | 556篇 |
临床医学 | 1811篇 |
内科学 | 3712篇 |
皮肤病学 | 338篇 |
神经病学 | 1746篇 |
特种医学 | 984篇 |
外国民族医学 | 25篇 |
外科学 | 2416篇 |
综合类 | 150篇 |
一般理论 | 6篇 |
预防医学 | 2115篇 |
眼科学 | 221篇 |
药学 | 1664篇 |
中国医学 | 58篇 |
肿瘤学 | 1043篇 |
出版年
2022年 | 138篇 |
2021年 | 278篇 |
2020年 | 179篇 |
2019年 | 239篇 |
2018年 | 313篇 |
2017年 | 235篇 |
2016年 | 280篇 |
2015年 | 332篇 |
2014年 | 425篇 |
2013年 | 608篇 |
2012年 | 895篇 |
2011年 | 934篇 |
2010年 | 512篇 |
2009年 | 527篇 |
2008年 | 877篇 |
2007年 | 870篇 |
2006年 | 879篇 |
2005年 | 855篇 |
2004年 | 783篇 |
2003年 | 764篇 |
2002年 | 725篇 |
2001年 | 575篇 |
2000年 | 619篇 |
1999年 | 509篇 |
1998年 | 223篇 |
1997年 | 168篇 |
1996年 | 141篇 |
1995年 | 168篇 |
1994年 | 200篇 |
1993年 | 268篇 |
1992年 | 597篇 |
1991年 | 553篇 |
1990年 | 451篇 |
1989年 | 313篇 |
1988年 | 288篇 |
1987年 | 284篇 |
1986年 | 238篇 |
1985年 | 283篇 |
1984年 | 211篇 |
1983年 | 151篇 |
1982年 | 127篇 |
1981年 | 131篇 |
1979年 | 169篇 |
1978年 | 139篇 |
1977年 | 131篇 |
1976年 | 144篇 |
1975年 | 148篇 |
1974年 | 183篇 |
1973年 | 156篇 |
1971年 | 135篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
The complexity of the RHD and RHCE genes, which is the greatest of all blood group systems, confounds analysis at the molecular level. RH DNA typing was introduced in 1993 and has been applied to prenatal testing. PCR-SSP analysis covering multiple polymorphisms was recently introduced for the screening and initial characterization of partial D. Our objective is to summarize the accrued knowledge relevant to the approaches to Rh phenotype prediction by DNA typing, their possible applications beyond research laboratories and their limitations. The procedures, results and problems encountered are highly detailed. It is recommended that DNA typing comprises an analysis of more than one polymorphism. We discuss future directions and propose a piecemeal approach to improve reliability and cost-efficiency of blood group genotyping that may eventually replace the prevalent serology-based techniques even for many routine tasks. Transfusion medicine is in the unique position of being able to utilize the most extensive phenotype databases available to check and develop genotyping strategies. 相似文献
102.
H C Koch W Burmeister N Liappis S Soetadji D Wagner B Langner 《Klinische P?diatrie》1991,203(3):167-172
In 73 healthy (group I) and 32 children and juveniles with insulin dependent diabetes mellitus (IDDM, group II) urinary albumin excretion is determined by radioimmunoassay (RIA). In both groups albumin excretion is observed in every urine sample when measured by RIA (mean +/- SD: group I: 7-19 h: 5.17 +/- 5.28 mg, 19-7 h: 3.86 +/- 4.00 mg, 24 h: 9.03 +/- 8.60 mg; group II: 7-19 h: 6.68 +/- 6.86 mg, 19-7 h: 3.46 +/- 2.82 mg, 24 h: 10.13 +/- 9.25 mg). No significant difference is detected between the values of the two groups. However in diabetic patients a significant difference is observed between diurnal and nocturnal urinary albumin excretion. Microalbuminuria is defined as an albumin excretion above 30 mg/d and is present in 6.9% of the values in group I and in 3.1% in group II. The physiological limits of microalbuminuria in children and juveniles compared to adults and several methods of urine sampling are discussed. 相似文献
103.
Sensitivity and specificity of screening for Down syndrome with alpha-fetoprotein, hCG, unconjugated estriol, and maternal age. 总被引:4,自引:0,他引:4
The sensitivity and specificity of maternal serum screening for Down syndrome with different biochemical markers were evaluated. Detection rates with different combinations of maternal serum alpha-fetoprotein (MSAFP), hCG, and unconjugated estriol (uE3) were established by retrieving and analyzing 54 serum specimens from women with confirmed Down syndrome pregnancies, compared with 657 specimens from women with normal outcomes. With a risk cutoff of 1:270 at the second trimester, the detection rate with MSAFP, hCG, and uE3 was two to three times higher than with MSAFP alone. With all three markers, the detection rate for Down syndrome increased from 50 to 77% as maternal age increased, and was 60% in a representative screened population. If uE3 was omitted, the detection rate decreased from 60 to 48%. One thousand women were screened prospectively, either with MSAFP or with all three markers prospectively, either with MSAFP or with all three markers and 4.1% with MSAFP. With the three markers, the positive predictive value for Down syndrome was 2.2% overall and as high as 5.9% in older women. Therefore, the addition of hCG and uE3 to the maternal serum screen increases the positive predictive value by 50-300%, depending on maternal age. These results confirm the efficacy of screening for Down syndrome using maternal age and three serum markers. 相似文献
104.
Karl‐Jürgen Br Stanislaw Brehm Michael Karl Boettger Gerd Wagner Silke Boettger Heinrich Sauer 《European Journal of Pain》2006,10(5):467-471
An altered perception of pain has been described for several psychiatric disorders. To date the influence of adjustment disorders (AD) on pain perception has not been described. Here, we investigated perception of experimentally induced pain in 15 patients suffering from AD (subtype with depressive symptoms) and controls matched for age and sex. Thresholds and tolerances were assessed for thermal and electrical pain on both sides of the body. We found an overall increase of pain thresholds and tolerances in AD patients as compared to controls, predominately on the right side of the body. Analogue findings have been reported for pain perception in major depressive disorder (MDD). Of the data obtained, only thermal pain threshold on the right arm correlated with the severity of depressive symptoms. Although the underlying pathology is elusive it is likely that the mechanisms for reduced pain sensitivity are comparable in MDD and AD. 相似文献
105.
106.
107.
The effect of pinacidil, a new antihypertensive vasodilator, was studied in vitro upon human and porcine Corpus cavernosum and in vivo upon simian Corpus cavernosum. In vitro, pinacidil incubation (10(-5)-10(-3) M) was found to induce a concentration-dependent inhibition of the tissue response to norepinephrine (NE) and high potassium (K+). Likewise a concentration-related relaxation of the tissue, precontracted with either NE or K+, was seen using pinacidil 10(-5)-10(-3) M. Depending on the concentration applied, spontaneous activity as well as tone and amplitude of the contractions were reduced until total relaxation of the tissue was obtained with a pinacidil incubation of 10(-3) M. In vivo, 5 mg pinacidil in 0.3 ml solution was injected intracavernosally in 17 monkeys. Sixteen monkeys developed tumescence and 10, rigidity of the penis as well. Only one of 5 showed a decrease in the systemic blood pressure. Pinacidil might be of clinical interest as an agent facilitating erection when given intravernosally. 相似文献
108.
Cyclic amides of N alpha-arylsulfonylated 4-amidinophenylalanine are specific, highly potent inhibitors of thrombin. Introduction of amino acids between the arylsulfonyl blocking group and amino nitrogen influence particularly the antithrombin activity. By the use of glycine as spacer the compounds become tight binding thrombin inhibitors, while introduction of other omega-amino acids, Gly-Gly, L-Pro, Gly-L-Pro or L-Pro-Gly, reduces the specificity and potency of thrombin inhibition. Substitution of the arylsulfonyl blocking group for a heteroarylsulfonyl residue or an aryl residue causes a decrease in antithrombin activity, while substitution for a benzoyloxycarbonyl blocking group has only slight influence. It is concluded that the N alpha-moiety is of decisive importance for the antithrombin activity of derivatives of 4-amidinophenylalanine. 相似文献
109.
Reepithelialization of experimental scalds effected by topically applied superoxide dismutase: controlled animal studies 总被引:1,自引:0,他引:1
Karola Vorauer-Uhl MD ; Eckhard Fürnschlief MD ; Andreas Wagner MD ; Boris Ferko MD ; Hermann Katinger MD 《Wound repair and regeneration》2002,10(6):366-371
Highly reactive metabolites, such as oxygen free radicals, initiate a cascade of inflammatory processes in thermally damaged skin, leading to enhanced tissue loss and delayed wound healing. The extent of tissue necrosis in the zone of stasis is of prognostic significance in the wound healing process. In this study, the effect of oxygen free radical removal by recombinant human-Cu/Zn-superoxide dismutase, given in three different formulations during the inflammatory postburn phase and wound repair, was examined. Recombinant human superoxide dismutase was either injected directly into the lesions, spread as enzyme-containing gel onto the burned tissue, or encapsulated into liposomes consisting of 1,2 dipalmitoy-sn-glycero-3-phosphocholine, cholesterol and stearylamine, suspended into a hydrophilic gel and administered to burned animals immediately after trauma. Controls were treated with plain gel or kept untreated. Edema formation, size of lesions, deepening of necrosis, and reepithelialization were examined. Results indicate that superoxide dismutase treatment resulted in reduced and faster recruitment of edema formation, smaller wound sizes, and minor tissue necrosis compared to the controls, thus resulting in significantly faster reepithelialization after 3 weeks. These animal studies on the efficacy of liposomal oxygen free radical scavenger showed accelerated wound healing in all parameters tested. 相似文献
110.
There is some controversy over the treatment of acromioclavicular injuries. The use of the Rockwood classification as the basis for decisions on whether operative or nonoperative treatment is indicated is discussed critically, and the authors' preferred operative technique is described and illustrated by examples. We treat injuries classified according to the Rockwood classification as types I and II with conservative methods. In type III injuries the patient's age, job and free time activities determine whether or not surgery is indicated. In the case of type IV or type VI injuries we always perform temporary internal fixation of the acromioclavicular joint, using transarticular K-wire fixation or hookplate osteosynthesis. Satisfactory results of both operative and nonoperative treatment are reported in the literature. The authors' own results are presented. 相似文献