全文获取类型
收费全文 | 26769篇 |
免费 | 1370篇 |
国内免费 | 66篇 |
专业分类
耳鼻咽喉 | 372篇 |
儿科学 | 2096篇 |
妇产科学 | 660篇 |
基础医学 | 3081篇 |
口腔科学 | 476篇 |
临床医学 | 1518篇 |
内科学 | 4921篇 |
皮肤病学 | 1004篇 |
神经病学 | 1221篇 |
特种医学 | 969篇 |
外科学 | 3937篇 |
综合类 | 936篇 |
一般理论 | 14篇 |
预防医学 | 1337篇 |
眼科学 | 1340篇 |
药学 | 2187篇 |
中国医学 | 142篇 |
肿瘤学 | 1994篇 |
出版年
2023年 | 164篇 |
2022年 | 405篇 |
2021年 | 772篇 |
2020年 | 440篇 |
2019年 | 510篇 |
2018年 | 735篇 |
2017年 | 478篇 |
2016年 | 695篇 |
2015年 | 620篇 |
2014年 | 966篇 |
2013年 | 1150篇 |
2012年 | 1624篇 |
2011年 | 1699篇 |
2010年 | 929篇 |
2009年 | 746篇 |
2008年 | 1289篇 |
2007年 | 1361篇 |
2006年 | 1174篇 |
2005年 | 1096篇 |
2004年 | 994篇 |
2003年 | 915篇 |
2002年 | 840篇 |
2001年 | 725篇 |
2000年 | 686篇 |
1999年 | 598篇 |
1998年 | 251篇 |
1997年 | 186篇 |
1996年 | 149篇 |
1995年 | 138篇 |
1994年 | 115篇 |
1993年 | 131篇 |
1992年 | 358篇 |
1991年 | 390篇 |
1990年 | 343篇 |
1989年 | 359篇 |
1988年 | 309篇 |
1987年 | 277篇 |
1986年 | 268篇 |
1985年 | 279篇 |
1984年 | 219篇 |
1983年 | 181篇 |
1979年 | 241篇 |
1978年 | 158篇 |
1977年 | 148篇 |
1976年 | 135篇 |
1975年 | 163篇 |
1974年 | 154篇 |
1973年 | 176篇 |
1972年 | 138篇 |
1971年 | 122篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Three hundred and seventeen recent clinical isolates were tested for in vitro susceptibility to the three cephalosporins available in India--cephalexin, cefazolin and cefotaxime by the Kirby--Bauer disc diffusion method. Cefazolin was the most effective cephalosporin against Gram positive cocci (71.8% sensitive) followed by cefotaxime (62.7%) and cephalexin (52.7%). Cefotaxime was very effective against commonly isolated Gram negative bacilli with only 10 (8.8%) isolates being resistant to it while 44 (39%) and 65 (57.5%) were resistant to cefazolin and cephalexin, respectively. All isolates of Pseudomonas aeruginosa were resistant to cephalexin and cefazolin and only 29 (32.6%) were sensitive to cefotaxime. 相似文献
32.
33.
Exposure to air pollution affects pulmonary functions adversely. Effect of exposure to pollution on diurnal variation of peak flow was assessed in healthy students. Three hundred healthy age-matched nonsmoker students were studied. They were categorized into two groups on the basis of their residence: commuters and living on campus. Peak expiratory flow (PEF) recordings were made twice daily for 2 days with the Pink City Flow Meter. The measurement was then used to calculate for each subject the amplitude percentage mean, which is an index for expressing PEF variability for epidemiological purposes (Higgins BG, Britton JR, Chinns Jones TD, Jenkinson D, Burnery PG, Tattersfield AE. Distribution of peak expiratory flow variability in a population sample. Am Rev Respir Dis 1989; 140:1368-1372). Air pollution parameters were quantified by measurement of sulfur dioxide (SO2), oxides of nitrogen (NO2), carbon monoxide (CO), and respirable suspended particulate matter (RSPM) in the ambient air at the campus and on the roadside. The mean values of PEF variability (amplitude percent mean) in the students living on campus and in the commuters were 5.7 +/- 3.2 and 11 +/- 3.6, respectively (P < .05). Among the commuters, maximum number of subjects showed amplitude percentage mean PEFR at the higher end of variability distribution, as compared to the students living on campus, among whom the majority of subjects fell in the lower ranges of variability distribution. The ambient air quality parameters, namely SO2, NO2, CO, and RSPM were significantly lower on the campus. It can be concluded that long-term periodic exposure to air pollution can lead to increased PEF variability even in healthy subjects. Measurement of PEF variability may prove to be a simple test to measure effect of air pollution in healthy subjects. 相似文献
34.
N Singh R Agarwal D Gupta M R Shivaprakash A Chakrabarti 《The European respiratory journal》2006,28(3):662-664
Phaeohyphomycosis is a disease caused by dematiaceous fungi. Here, the first culture-proven case of mediastinal mass due to Fonsecaea pedrosoi is reported. The patient was a 40-yr-old male who had presented with history of dyspnoea and dysphagia. Computed tomography of the chest disclosed a mediastinal mass. Cultures of a specimen from the mediastinum grew Fonsecaea pedrosoi. The patient received amphotericin B and itraconazole and showed a remarkable recovery. Repeat computed tomography revealed a reduction in the mediastinal mass. The case highlights the need for a high degree of clinical suspicion and appropriate histopathological and mycological examination of clinical specimens. 相似文献
35.
Nitin Gupta Saurabh Varshney S. S. Bist Pratima Gupta Rajat Bhatia 《Indian journal of otolaryngology and head and neck surgery》2007,59(4):309-312
Retropharyngeal abscesses were fairly common in preantibiotic era but the advent of antibiotics has reduced the overall incidence
of these abscesses. They still continue to occur specially in developing world and carry significant morbidity and even mortality
if not managed properly. The prevalence of this abscess in the young children pose a bigger challenge, as the examination
of oral cavity is difficult. Emphasis is placed on the age, sex, type, and duration of symptoms, bacteriology, methodology
of diagnosis, therapy and complications. With proper antibiotic cover and surgical management, majority of patients today
survive without major residual squeal. Hereby we present a series of 15 cases of retropharyngeal abscess. 相似文献
36.
Carcinoma of the urinary bladder presenting during pregnancy is rare. We report two such cases presenting with gross hematuria,
both of which were managed by transurethral electroresection of the tumor; there was no adverse effect on the pregnancies.
Transurethral resection thus appears to be the procedure of choice in the management of this condition, and carries minimal
morbidity even when performed during pregnancy.
EDITORIAL COMMENT: As these authors point out, bladder tumors are rare in pregnancy and frequently present as gross hematuria
that is mistaken for vaginal bleeding due to the pregnancy. Ultrasound is very helpful in distinguishing the causes of bleeding,
and will show the bladder filled with clots and frequently the tumor as well. Standard transurethral resection is effective
when performed during pregnancy, bearing in mind the need to heed to the anesthetic risks inherent in any operative procedure
during pregnancy. 相似文献
37.
38.
Administration of Embelin, an experimental antifertility agent, to male rats (20 mg/kg body wt/day, daily for 15 and 30 days), caused an elevation in the uptake of D-glucose, L-alanine, L-leucine, and calcium in the small intestinal segments. An increase was also noted in the intestinal brush border membrane (BBM)-associated enzymes, sucrase, lactase, maltase, alkaline phosphatase, and leucine aminopeptidase in both the intestinal homogenates and partially purified BBM preparations, particularly after 30-day administration of the drug. Embelin treatment also caused a significant increase in the microsomal glucose-6-phosphatase and the cytosolic enzyme, lactate dehydrogenase. In the Embelin-treated animals BBM-associated total lipids, phospholipids, cholesterol, triacylglycerol, unesterified fatty acids, ganglioside-sialic acids as well as the cholesterol/phospholipids molar ratio showed a considerable increase. All these changes in the Embelin-treated animals were restored back to the normal or near normal biochemical makeup when the drug therapy was withdrawn and the animals were allowed to recover for another 15 and 30 days, respectively. 相似文献
39.
S. C. Srivastava S. C. Gupta A. P. Singh 《Indian journal of otolaryngology and head and neck surgery》1993,45(4):188-190
In the present study 35 patients with preforated and 15 cases with intact ear drums, were studied and eustachian tube function
was assessed by Saccharine test. Bortnick-Miller test, and manual impedance audiometry. The merits and demerits of one over
the other were evaluated. It was observed thal more than one test when employed provides better information as every test
has its own advantages and limitations 相似文献
40.
Induction of MHC class II expression in recipient tissues caused by allograft rejection 总被引:2,自引:0,他引:2
MHC class II antigens (DR) are not commonly expressed on parenchymal cells of kidney and liver except when they are allografts undergoing rejection. The objective of this study was to determine whether allograft rejection can also induce DR upregulation in parenchymal cells of autologous recipient organs. Dogs had unilateral renal autografts to facilitate kidney sampling. All kidneys were tubular cell DR-negative. After 8-14 days each dog received a tubular cell DR-negative allograft. Tubular cell DR became positive in both allograft and autograft simultaneously, its onset and intensity correlating with blast cell infiltration and rejection in the allograft. Blast cells were first detected in the autograft after allograft nephrectomy, and then disappeared as autograft tubular cell DR diminished over the next 6-8 days. This was reproduced on repeat allografting. In 2 untreated dogs hepatocytes became positive on day 4, with no hepatic blast infiltrate. Four other dogs received cyclosporine immunosuppression. Allograft and autograft tubular cell DR, and hepatocyte DR, increased in all dogs, but were delayed while on CsA until onset of rejection despite transient earlier allograft blast infiltration. Downregulation in autograft and liver occurred together after allograft nephrectomy. An interferon-like substance appeared in plasma after allografting in association with the DR changes in native kidney and liver. Renal allorejection therefore induces upregulation of parenchymal DR expression in autologous liver and kidney of the recipient. It is probably mediated by an interferon-like substance derived from cells infiltrating the allograft. The effect is modified by CsA. 相似文献