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   668篇
  免费   30篇
  国内免费   14篇
儿科学   44篇
妇产科学   4篇
基础医学   68篇
口腔科学   17篇
临床医学   111篇
内科学   102篇
皮肤病学   8篇
神经病学   25篇
特种医学   191篇
外科学   32篇
综合类   32篇
预防医学   10篇
眼科学   2篇
药学   55篇
肿瘤学   11篇
  2020年   4篇
  2019年   2篇
  2018年   3篇
  2017年   4篇
  2016年   6篇
  2015年   6篇
  2014年   16篇
  2013年   13篇
  2012年   4篇
  2011年   8篇
  2010年   13篇
  2009年   18篇
  2008年   5篇
  2007年   18篇
  2006年   10篇
  2005年   11篇
  2004年   5篇
  2003年   12篇
  2002年   6篇
  2001年   9篇
  2000年   3篇
  1999年   20篇
  1998年   39篇
  1997年   47篇
  1996年   38篇
  1995年   39篇
  1994年   23篇
  1993年   26篇
  1992年   17篇
  1991年   19篇
  1990年   16篇
  1989年   14篇
  1988年   23篇
  1987年   23篇
  1986年   24篇
  1985年   19篇
  1984年   9篇
  1983年   8篇
  1982年   18篇
  1981年   12篇
  1980年   22篇
  1979年   4篇
  1978年   13篇
  1977年   22篇
  1976年   12篇
  1975年   10篇
  1968年   3篇
  1963年   2篇
  1960年   6篇
  1943年   1篇
排序方式: 共有712条查询结果,搜索用时 15 毫秒
1.
2.
3.
卢日刚 《药学学报》1992,27(11):871-874
This paper provides a basic principle and experimental technique of derivative signal multiplier spectrophotometry in multicomponent mixture. A microcomputer was used to process the spectral data measured on a manual spectrophotometer (UV-7520) for the determination of moroxydine hydrochloride in Gan Mao Qing capsules. Quantitative analysis of multicomponent mixture can be done without sample separation. The selection of optimal wavelength pairs is performed through the program with a computer. The method needs no special spectrophotometer and is simple, rapid and easy to operate. The mean recovery was 99.98 +/- 0.53% (n = 12).  相似文献   
4.
5.
An original approach to the measurement of analytes in clinical chemistry has now become available, in which dry reagent strip technology is linked to measurement by reflectance spectroscopy. The present studies have evaluated the performance of the first of these test systems—for uric acid, urea and glucose, in serum—by comparison with conventional liquid chemistry methods. Satisfactory performance in terms of both precision and accuracy was obtained for all three test systems, the current “state-of-the-art” performance criteria being met; the Seralyzer system proved reliable and easy to use in the hands of trained operators. It should find a place as a “Stat” analyser in the laboratory, in specified wards and in Health Centres.  相似文献   
6.
7.
The recent improvements in the treatment of cancer by chemo- and radiotherapy have led to a significant increase in the survival rates of patients with malignant disease, but at the expense of distressing side effects. One major problem, especially for younger patients, is that aggressive therapy destroys a significant proportion of the follicular population, which can result in either temporary or permanent infertility. Freeze-banking pieces of ovarian cortex prior to treatment is one strategy for preserving fecundity. When the patient is in remission, fertility could, theoretically, be restored by autografting the thawed tissue at the orthotopic site or by growing isolated follicles to maturity in vitro. Recent studies have found good follicular survival in frozen-thawed human ovarian tissue but to optimize the process an effective cryopreservation method needs to be developed. An essential part of such a technique is to permeate the tissue with a cryoprotectant to minimize ice formation and the extent of this equilibration is an important determinant of post-thaw cellular survival. In the current study, we have investigated the diffusion of four cryoprotective agents into human tissue at both 4 degrees C and 37 degrees C. We have also studied the effect of adding different concentrations of the non penetrating cryoprotective agent, sucrose, to the freezing media using the release of lactate dehydrogenase as a measure of its protective effect. At 4 degrees C propylene glycol and glycerol penetrated the tissue significantly slower than either ethylene glycol or dimethyl sulphoxide. At the higher temperature of 37 degrees C all four cryoprotectants penetrated at a faster rate, however concern about enhanced toxicity prevents the use of these conditions in practice. Thus, the results suggest that the best method of preparing tissue for freezing is exposure for 30 min to 1.5 M solutions of ethylene glycol or dimethyl sulphoxide at 4 degrees C; this achieved a mean tissue concentration that was almost 80% that of the bathing solution. We also report that the addition of low concentrations of sucrose to the freezing medium does not have a significant protective effect against freezing injury.   相似文献   
8.
9.
Summary 1. Cardiac ventricular muscle of adult, anesthetized, open-chest dogs, guinea pigs, and rabbits given artificial respiration was compressed by means of a pair of –190°C cold aluminum tongs in situ in 0.02–0.4 seconds to frozen plates 0.4–1.5 mm in thickness.2. Determinations of phosphates extracted from the finely powdered plates with 0° or –35°C cold perchloric acid yielded, among other results, the following values per gram of dog, guinea pig, and rabbit myocardium, respectively: 1.9, 2.0, and 1.9 moles of orthophosphate; and 12.8, 10.9, and 8.2 moles of N-phosphorylcreatine (labile phosphate). Bound creatine, analyzed in extracts of guinea pig and rabbit hearts, corresponded quantitatively to the labile phosphate.3. Cardiac muscle samples which were excised and immediately immersed in liquid air contained 3–4 times as much orthophosphate and only a little more than half as much phosphorylcreatine as the metal-cooled tissue. There was also less total acid-soluble phosphate present. The sum of orthophosphate and phosphorylcreatine and the amounts of 10-minute-phosphate and of total creatine were not significantly altered by excision and freezing in liquid air.4. The rapidly beating hearts contained per gram (a) less orthophosphate than is found in the resting skeletal musculature; and (b) as much as or more phosphorylcreatine than there exists, according to data in the literature, in certain types of skeletal muscle in the resting state.5. The problem of obtaining a warm-blooded heart, or a part of it, for analysis without inducing changes in chemical composition is considered in relation to the anatomy of the organ. The advantage is noted which the cooling tongs technique affords in this regard over other methods of tissue freezing.

Mit 1 Textabbildung

Vorläufige Mitteilung: Wollenberger, Krause u. Wahler (1958).  相似文献   
10.
Achromatopsia is an autosomal recessive disease of the retina, characterized clinically by an inability to distinguish colors, impaired visual acuity, nystagmus and photophobia. A genome-wide search for linkage was performed using an inbred Jewish kindred from Iran. To facilitate the genome-wide search, we utilized a DNA pooling strategy which takes advantage of the likelihood that the disease in this inbred kindred is inherited by all affected individuals from a common founder. Equal molar amounts of DNA from all affected individuals were pooled and used as the PCR template for short tandem repeat polymorphic markers (STRPs). Pooled DNA from unaffected members of the kindred was used as a control. A reduction in the number of alleles in the affected versus control pool was observed at several loci. Upon genotyping of individual family members, significant linkage was established between the disease phenotype and markers localized on chromosome 2. The highest LOD score observed was 5.4 (theta = 0). When four additional small unrelated families were genotyped, the combined peak LOD score was 8.2. Analysis of recombinant chromosomes revealed that the disease gene lies within a 30 cM interval which spans the centromere. Additional fine-mapping studies identified a region of homozygosity in all affected individuals, narrowing the region to 14 cM. A candidate gene for achromatopsia was excluded from this disease interval by radiation hybrid mapping. Linkage of achromatopsia to chromosome 2 is an essential first step in the identification of the disease-causing gene.   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