全文获取类型
收费全文 | 379806篇 |
免费 | 24329篇 |
国内免费 | 2813篇 |
专业分类
耳鼻咽喉 | 5219篇 |
儿科学 | 8238篇 |
妇产科学 | 10089篇 |
基础医学 | 53209篇 |
口腔科学 | 11857篇 |
临床医学 | 30118篇 |
内科学 | 78594篇 |
皮肤病学 | 8552篇 |
神经病学 | 27246篇 |
特种医学 | 13922篇 |
外国民族医学 | 82篇 |
外科学 | 60685篇 |
综合类 | 9973篇 |
现状与发展 | 1篇 |
一般理论 | 64篇 |
预防医学 | 17432篇 |
眼科学 | 9444篇 |
药学 | 31032篇 |
1篇 | |
中国医学 | 2195篇 |
肿瘤学 | 28995篇 |
出版年
2021年 | 2622篇 |
2019年 | 2735篇 |
2018年 | 4537篇 |
2017年 | 3449篇 |
2016年 | 3541篇 |
2015年 | 4036篇 |
2014年 | 5720篇 |
2013年 | 7396篇 |
2012年 | 10085篇 |
2011年 | 10256篇 |
2010年 | 6213篇 |
2009年 | 5861篇 |
2008年 | 9490篇 |
2007年 | 10339篇 |
2006年 | 10255篇 |
2005年 | 9319篇 |
2004年 | 8829篇 |
2003年 | 8554篇 |
2002年 | 8230篇 |
2001年 | 28259篇 |
2000年 | 28799篇 |
1999年 | 23668篇 |
1998年 | 5174篇 |
1997年 | 4254篇 |
1996年 | 3833篇 |
1995年 | 3490篇 |
1994年 | 3109篇 |
1993年 | 2851篇 |
1992年 | 16062篇 |
1991年 | 14835篇 |
1990年 | 14166篇 |
1989年 | 13971篇 |
1988年 | 12591篇 |
1987年 | 12078篇 |
1986年 | 11114篇 |
1985年 | 10328篇 |
1984年 | 6916篇 |
1983年 | 5609篇 |
1982年 | 2723篇 |
1979年 | 5479篇 |
1978年 | 3350篇 |
1977年 | 2972篇 |
1975年 | 2642篇 |
1974年 | 3067篇 |
1973年 | 2868篇 |
1972年 | 2831篇 |
1971年 | 2781篇 |
1970年 | 2511篇 |
1969年 | 2543篇 |
1968年 | 2253篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Tayama K; Takamori S; Mitsuoka M; Hiraki H; Ohtsuka S; Hayashi A; Aoyama Y; Shirouzu K 《Japanese journal of clinical oncology》1997,27(6):401-405
The aim of this study was to investigate retrospectively the efficacy of
expandable metallic stents (EMSs) for severe respiratory distress in
patients with central airway obstruction. Twenty patients with central
airway obstructions were treated with an EMS. An intraluminal stricture was
present in 15 and an extraluminal stricture in 5 patients. Of the 15
patients with intraluminal stenosis, 11 exhibited symptomatic improvement.
All 11 patients had tumor infiltration occupying less than 50% of the
endoluminal diameter. The other four patients with intraluminal stenosis
had tumor infiltration occupying > 50% of the endoluminal diameter and
demonstrated no improvement. All five patients with extraluminal stenosis
were improved. EMS is useful for an extraluminal stricture in the central
airway and the effect of EMS for intraluminal stenosis is related to the
degree of infiltration and of tumor progression itself.
相似文献
92.
93.
降糖饮降糖作用的实验研究 总被引:2,自引:0,他引:2
降糖饮以8.1,15.0,30。0g.kg^-1灌胃予鼠,连续10天。结果表明降饮对正常小鼠大鼠血糖血脂无明显影响,但对四氧嘧啶或链脲霉素引起的大鼠高血糖及蛋黄引起的小鼠高脂血症,高胆固醇饲料引起的大鼠高脂血症均有显著降低作用。本研究为降糖饮的应用提供了可靠的药理学依据。 相似文献
94.
The 2.0-Å resolution crystal structure of a trimeric antibody fragment with noncognate VH–VL domain pairs shows a rearrangement of VH CDR3
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Xue Y. Pei Philipp Holliger Alexey G. Murzin Roger L. Williams 《Proceedings of the National Academy of Sciences of the United States of America》1997,94(18):9637-9642
The 2.0-Å resolution x-ray crystal structure of a novel trimeric antibody fragment, a “triabody,” has been determined. The trimer is made up of polypeptides constructed in a manner identical to that previously described for some “diabodies”: a VL domain directly fused to the C terminus of a VH domain—i.e., without any linker sequence. The trimer has three Fv heads with the polypeptides arranged in a cyclic, head-to-tail fashion. For the particular structure reported here, the polypeptide was constructed with a VH domain from one antibody fused to the VL domain from an unrelated antibody giving rise to “combinatorial” Fvs upon formation of the trimer. The structure shows that the exchange of the VL domain from antibody B1-8, a Vλ domain, with the VL domain from antibody NQ11, a Vκ domain, leads to a dramatic conformational change in the VH CDR3 loop of antibody B1-8. The magnitude of this change is similar to the largest of the conformational changes observed in antibody fragments in response to antigen binding. Combinatorial pairing of VH and VL domains constitutes a major component of antibody diversity. Conformationally flexible antigen-binding sites capable of adapting to the specific CDR3 loop context created upon VH–VL pairing may be employed by the immune system to maximize the structural diversity of the immune response. 相似文献
95.
Antigenicity of a synthetic peptide from glucosyltransferases of Streptococcus mutans in humans. 总被引:1,自引:0,他引:1
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Human salivary immunoglobulin A (IgA) and serum IgG antibodies to the Streptococcus mutans glucosyltransferases (Gtfs) and to a synthetic peptide of 19 amino acids from a conserved region in the Gtfs (residues 435 to 453) were determined in young adults by enzyme-linked immunosorbent assay. Varying levels of antibody to Gtfs were detected in saliva or serum, with significantly higher levels of antibody to GtfD than to GtfB/C or GtfC. Anti-Gtf IgA levels in saliva did not correlate with those of IgG in serum. Caries-free (CF) volunteers exhibited significantly higher salivary IgA antibody levels to the peptide and to GtfB/C or GtfC than did the caries-active (CA) subjects. Preincubation of CF saliva and serum with the peptide inhibited the antibodies to the Gtfs in a dose-dependent manner, whereas preincubation of the samples from the CA group resulted in only partial inhibition. Our results indicated that this 19-amino-acid peptide includes one of the major B-cell epitopes of Gtfs and that CF individuals have higher titers of antibodies than CA subjects. 相似文献
96.
Congenital intermaxillary fusion is a rare anomaly. Combination of the anomaly with any type of facial cleft is extremely rare. Death in a majority of these patients as a result of feeding and aspiration problems in early life may have caused the reports to be limited. In this article a 5-year-old patient, probably the first in the literature having Tessier type VI-VII facial cleft combination associated with bimaxillary fusion and anophthalmia on the right side, is presented. The patient has survived on fluid meal through a very small opening for 5 years. The features of the case are presented, and the time and method of the management of such a rare anomaly are discussed with a review of the literature. 相似文献
97.
T F Kruger J P Van der Merwe H J Odendaal F S Stander G M Grobler V A Hulme E L Erasmus K Coetzee M L Windt Y Swart 《Suid-Afrikaanse tydskrif vir geneeskunde》1990,77(12):634-636
The results of the in vitro fertilisation programme at Tygerberg Hospital for the period April 1983 to January 1988 are presented. Of the 1117 laparoscopies performed, 825 patients reached the transfer stage. A live-birth rate of 9.3% was achieved. The pregnancy rate after transfer of 4 embryos was 25.9% compared with 15.4% after 2 embryos and 10.8% after 3 embryos (P = less than 0.0001). The multiple pregnancy rate was 2.8% in the group receiving 2 embryos and 11.7% and 10.4% in those receiving 3 and 4 embryos, respectively. Of the 77 successful pregnancies (90 babies), 1 baby died at 34 weeks' gestation as the result of abruptio placentae due to preeclampsia and 1 cot death occurred. The only congenital abnormality encountered was a cleft palate. 相似文献
98.
Physical therapy without anesthesia or plaster casts was used to treat 338 cases of clubfoot (CF). Our technique is based on progressive sequential manipulations at birth. We first reduce the varus and later the equinus component of the CF. The gentle stretches used in this technique are complemented by active physiotherapy stimulating the muscles, and then a simple splint is suited to the foot to fix its degree of realignment. When used alone, this technique achieves 77% good and fair results. In resistant cases, complementary surgery was used. We obtained 96% good and fair results. 相似文献
99.
K Y Mumcuoglu J Miller R Gofin B Adler F Ben-Ishai R Almog D Kafka S Klaus 《Public health reviews》1990,18(4):335-344
BACKGROUND: The aim was to determine the influence of the socioeconomic status of the family and the hygienic practices in the home on the prevalence of head lice infestation in children. METHODS: The study was carried out by analyzing the answers to a standardized epidemiological questionnaire given to parents of school children aged 4-17 in Bet Shemesh, a medium-sized urban town 25 km from Jerusalem. RESULTS: Of 3,000 questionnaires distributed, 958 (31.9%) were completed and returned. The majority of the children (72.4%) had been previously infested with lice. Half of them had other family members, mainly brothers and sisters, who had been infested in the past with lice. In 97.5% of the families the mother was responsible for examining the children for lice, and for carrying out treatment when infestation was present. An association was found between presence of lice infestation and mother's education, age of child, and frequency of shampooing, combing, and examination for lice. There was no association between infestation rates and mother's country of origin, crowding in the home, and the sharing of combs, brushes, hats, scarves, towels, and clothes. CONCLUSIONS: There is evidence that the incidence of lice infestation depends on the hygienic practices in the home rather than on the socioeconomic status of the family or sharing of personal articles among family members. 相似文献
100.
A Kubota A Okada K Imura H Kawahara R Nezu S Kamata Y Takagi 《Journal of pediatric surgery》1990,25(6):618-621
The effect of metronidazole (MNZ) on hepatic dysfunction associated with total parenteral nutrition (TPN) in neonates was investigated. Neonates receiving TPN for more than 2 weeks were divided into three groups. In group 1, TPN was given alone, in group 2, 25 mg/kg/d of MNZ was administered intravenously for the first 2 weeks of TPN, and in group 3, 50 mg/kg/d of MNZ was given for the first 3 weeks of TPN. Several parameters of liver function tests (LFTs) during the first 4 weeks of TPN were compared among these three groups. There was no significant difference of these parameters between group 1 and group 2. Although there was no significant difference of alkaline phosphatase, gamma-glutamyl transpeptidase, direct bilirubin, and total bile acid between groups 1 and 3, transaminase (glutamic oxaloacetic, glutamic pyruvic) of group 3 remained significantly lower than those of group 1. In conclusion, the administration of MNZ 50 mg/kg/d for 3 weeks, at least, prevented the elevation of transaminase during TPN in neonates, suggesting the possible involvement of intestinal anaerobic flora in the pathogenesis of TPN-associated liver dysfunction. 相似文献