首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   15063篇
  免费   922篇
  国内免费   69篇
耳鼻咽喉   220篇
儿科学   446篇
妇产科学   242篇
基础医学   1724篇
口腔科学   406篇
临床医学   1244篇
内科学   3374篇
皮肤病学   337篇
神经病学   871篇
特种医学   466篇
外国民族医学   5篇
外科学   2259篇
综合类   383篇
一般理论   8篇
预防医学   1014篇
眼科学   393篇
药学   1482篇
  1篇
中国医学   187篇
肿瘤学   992篇
  2023年   177篇
  2022年   501篇
  2021年   736篇
  2020年   432篇
  2019年   578篇
  2018年   664篇
  2017年   406篇
  2016年   517篇
  2015年   527篇
  2014年   676篇
  2013年   821篇
  2012年   1183篇
  2011年   1199篇
  2010年   751篇
  2009年   523篇
  2008年   811篇
  2007年   801篇
  2006年   719篇
  2005年   640篇
  2004年   542篇
  2003年   446篇
  2002年   406篇
  2001年   221篇
  2000年   199篇
  1999年   177篇
  1998年   82篇
  1997年   55篇
  1996年   56篇
  1995年   53篇
  1994年   51篇
  1993年   52篇
  1992年   93篇
  1991年   90篇
  1990年   87篇
  1989年   86篇
  1988年   59篇
  1987年   69篇
  1986年   55篇
  1985年   54篇
  1984年   48篇
  1983年   28篇
  1982年   26篇
  1981年   30篇
  1980年   27篇
  1979年   44篇
  1978年   30篇
  1977年   24篇
  1975年   28篇
  1974年   21篇
  1973年   26篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Assessment of completeness of vagotomy has always been an irksome and time-consuming affair. The commonly employed test of insulin-induced hypoglycaemia (Hollander) is tedious, risky and associated with practical limitations and theoretical objections, which have resulted in its being replaced by the modified sham feed technique in some centres. The postprandial alkaline tide is attributed to HCO3- release consequent to H+ secretion. Any procedure which reduces acid secretion is expected to affect the postprandial urinary pH. This study was performed to evaluate the effect of vagotomy on the postprandial alkaline tide by measuring prevagotomy and postvagotomy fasting and postprandial urinary pH. The results show that postprandial urinary pH falls after vagotomy and this method may be used to assess the completeness of vagotomy. The proposed test is convenient and may be used as a screening method in the assessment of vagotomy and other acid reducing operative procedures, if further validated, by comparison with already established tests.  相似文献   
3.
4.
Development of tolerance to the CNS effects of aminoglutethimide in mice   总被引:1,自引:0,他引:1  
Initially, there is a high incidence of CNS-depressant side-effects when the aromatase inhibitor, aminoglutethimide, is used in the treatment of patients with advanced breast cancer. Tolerance to these effects develops with continued dosing. This study examines the development of tolerance to various indices of CNS depression with the drug in mice. Single doses of aminoglutethimide induced a dose-dependent depression of spontaneous locomotor activity, rotarod performance, righting reflex and body temperature and a dose-related antileptazol activity. On repeated dosing with the drug, tolerance to these various activities occurred. The tolerance was found to be dose-dependent in the rotarod and righting reflex tests and time-dependent in the locomotor and body temperature tests. Although the results do not allow a determination of whether this clearly demonstrated phenomenon in the mouse is primarily functional or dispositional, the slow onset (14 days) for complete tolerance may be indicative of a functional mechanism.  相似文献   
5.
BACKGROUND AND PURPOSE: Marine luminous bacteria were isolated and identified from samples in shallow coastal waters of Taiwan during the relatively warm seasons. METHODS: Identification of the luminous isolates was performed based on differences of phenotypic and genotypic characteristics together with data from phylogenetic analysis. RESULTS: Twenty seven strains of marine luminous bacteria were isolated. They were divided into five types based on differences of phenotypic characteristics. However, they could be clustered into only two genotypes according to the analysis of restriction patterns of polymerase chain reaction-amplified 16S rRNA genes digested with various restriction enzymes. The characterization data together with the 16S rRNA gene-based phylogenetic analysis revealed that the isolates included in phenotype I (seven isolates) could be Photobacterium leiognathi, and those included in phenotypes II-V (twenty isolates) might be classified as Vibrio harveyi. However, phylogeny based on gyrB sequences indicated that phenotypes II-V could be classified into two species, V. harveyi and Vibrio campbellii. CONCLUSION: Culturable luminous bacteria in the shallow coastal waters of Taiwan during the sampling period are dominated by V. harveyi/campbellii and P. leiognathi, and the former species appeared to be more prevalent and numerous than the latter species in general.  相似文献   
6.
Emergency Room patients at Riverside General Hospital who are found by the attending physician to have depressed sensorium and altered personality are routinely subjected to urine tests for various drugs of abuse including phencyclidine (PCP). The findings of the laboratory analysis of these patients are presented in this paper. The toxicology laboratory of this hospital performs screening procedures for various drugs on urine specimens by thin layer chromatography. Drugs detected are confirmed by gas chromatography and a homogeneous enzyme immunoassay technique. In 1981, 1.6% of the urine specimens of patients in the above-mentioned category were found to be positive for PCP. This percentage increased sharply during 1982 (5.8%) and 1983 (5.6%). During 1984 and 1985 the percentage dropped to 4.2% and 4.6%. It is implied from data that the abuse of this drug in this area has leveled off. The data also indicated that PCP is predominantly used by young adults with ages ranging from 21 to 30 years. The abuse of this drug in people over 40 years of age is comparatively very small. Among users of this drug, 67.5% are men and 32.5% are women. Out of 68 women found to be abusing PCP, 5 delivered their babies in this hospital. PCP was detected in the urine specimens of each of these babies. Four out of the five infants showed withdrawal symptoms such as extreme irritability, jitteriness, hyperactivity with high pitched cries and a poor ability to take food.  相似文献   
7.
Sir, I read with great interest the letter by Higgins and co-workers[1].  相似文献   
8.
9.
Intravenous captopril in congestive heart failure   总被引:1,自引:0,他引:1  
Hemodynamic and neurohumoral effects of intravenous captopril were studied in ten patients with severe chronic congestive heart failure (NYHA Functional Class III and IV). Incremental bolus doses of captopril, titrated to a maximum cumulative dose of 15 mg, were given at 10-minute intervals. Systemic arterial pressure, mean pulmonary capillary wedge pressure, systemic vascular resistance, mean pulmonary artery pressure, and heart rate decreased (P less than .05). Cardiac index and stroke volume index increased (P less than .05). Maximum hemodynamic effects occurred after cumulative doses of 7 mg and were seen within 30 minutes after initiation of therapy; responses persisted for 30-90 minutes after the last dose. Plasma renin activity increased, and plasma atrial natriuretic factor concentration decreased. No adverse effects were observed with the use of intravenous captopril. Thus, intravenous captopril produces rapid and favorable hemodynamic improvement in advanced heart failure patients.  相似文献   
10.
J Musarrat  M Ahmad 《Mutagenesis》1991,6(3):207-211
Bacteriophage lambda-Escherichia coli complexes exhibited remarkable sensitivity to alkaline pH 10.0 at 37 degrees C. The decline in plaque forming units after alkali treatment was more pronounced in complexes with some of the radiation repair defective mutants of E. coli K-12, i.e. uvrArecA, recA, rer and lexA mutants as compared to those of uvrA, recB and wild-type strains. The red gene of lambda phage and recA gene of E. coli seem to have a complementary effect on the alkali induced lesions. Alkaline treatment to lysogenic lambda phage was also found to be mutagenic. An enhanced level of mutagenesis was observed when treated phage particles were allowed to adsorb on treated wild-type bacteria. Moreover, the alkali treatment to lysogen (lambda cI857-E. coli) resulted in prophage induction in nutrient broth even at 32 degrees C. Thus on the basis of these results the role of error prone SOS repair systems in the repair of alkali induced lesions in lysogenic bacteriophage lambda has been suggested.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号