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   1867篇
  免费   179篇
耳鼻咽喉   2篇
儿科学   76篇
妇产科学   19篇
基础医学   291篇
口腔科学   29篇
临床医学   240篇
内科学   471篇
皮肤病学   14篇
神经病学   178篇
特种医学   86篇
外国民族医学   1篇
外科学   184篇
综合类   37篇
一般理论   2篇
预防医学   198篇
眼科学   41篇
药学   123篇
  1篇
肿瘤学   53篇
  2021年   19篇
  2020年   18篇
  2019年   24篇
  2018年   21篇
  2017年   17篇
  2016年   30篇
  2015年   28篇
  2014年   44篇
  2013年   41篇
  2012年   80篇
  2011年   67篇
  2010年   40篇
  2009年   50篇
  2008年   62篇
  2007年   83篇
  2006年   71篇
  2005年   83篇
  2004年   92篇
  2003年   74篇
  2002年   70篇
  2001年   57篇
  2000年   59篇
  1999年   53篇
  1998年   21篇
  1997年   31篇
  1996年   22篇
  1995年   18篇
  1993年   16篇
  1992年   54篇
  1991年   45篇
  1990年   47篇
  1989年   40篇
  1988年   53篇
  1987年   41篇
  1986年   45篇
  1985年   24篇
  1984年   19篇
  1983年   25篇
  1982年   17篇
  1981年   17篇
  1979年   21篇
  1977年   25篇
  1976年   21篇
  1975年   17篇
  1974年   23篇
  1973年   16篇
  1972年   22篇
  1971年   24篇
  1970年   17篇
  1969年   15篇
排序方式: 共有2046条查询结果,搜索用时 31 毫秒
1.
2.
Ultrasound cystography in the diagnosis of vesicoureteric reflux   总被引:5,自引:0,他引:5  
Vesicoureteric reflux is common in children with urinary tract infection and may cause end-stage renal failure. The diagnosis is usually based on micturating cystourethrography (MCU). We describe an alternative technique using ultrasound during bladder infusion with agitated saline. Comparison of the 2 methods shows ultrasound to be 100% sensitive in the detection of grades 3 and 4 reflux. Conclusive evidence of reflux was seen in 2 cases where MCU was subsequently normal, questioning the role of MCU as the gold standard.  相似文献   
3.
Studies were undertaken to define the expression of cytokeratins in normal, hyperplastic and malignant epithelial cells from human prostate. Cytokeratin (CK) polypeptides, separated by two-dimensional electrophoresis, were identified by immunoblotting with CK-specific monoclonal antibodies. CK polypeptides 5, 7, 8, 15, 18 and 19 were identified in fresh normal and hyperplastic prostate. Expression of CK 15 has not been previously reported in human prostate. Analysis of central and peripheral zone tissues from human prostate did not reveal qualitative differences in CK expression between these areas. Epithelial cells harvested from fresh BPH tissue by percoll gradient centrifugation and propagated in vitro using selective culture techniques showed alterations in CK expression compared to intact human prostate. Specifically, CKs 6, 14, 16 and 17 were noted in cultured BPH epithelial cells but not fresh normal prostate or BPH tissue. Immunoblot analysis of the established prostate cancer cell lines PC3, DU145 and LNCAP showed expression of CKs 8 and 18 but not CKs 5, 7 and 15 which were observed in benign prostate. These studies further characterize CK expression in benign and malignant human prostate and provide insights which may be useful in differentiating normal, hyperplastic and malignant epithelial cells in the human prostate gland.  相似文献   
4.
5.
(1) Liver cirrhosis was induced in male rats by treatment with carbon tetrachloride and phenobarbitone for 130-142 days. Detailed histological examination showed all livers from rats treated with carbon tetrachloride had annular fibrosis, necrosis, loss of normal hepatic architecture and other features that were consistent with an established micronodular cirrhosis. (2) Plasma biochemical analysis showed a significant reduction in total protein concentration (13%), which was due entirely to a reduction in plasma albumin (29%). There were also large increases in the plasma activities of alkaline phosphatase (110%) and aspartate aminotransferase (159%), when compared to phenobarbitone-treated controls. Plasma cholesterol was also increased (67%), but other plasma analytes were not significantly altered. (3) The soleus (Type I), plantaris (Type II) and gastrocnemius (Types I and II) muscles were dissected and examined for possible differential effects. There were minor reductions in all three muscle weights, but these changes did not reach statistical significance. The protein, RNA and DNA concentrations, total muscle content and content relative to body weight in cirrhotic rats were also not significantly altered in any of the muscles. Cirrhosis did not cause any perturbations in derived parameters, i.e. amount of synthetic apparatus per cell, RNA/DNA ratio, apparent cell size, protein/DNA ratio and the capacity for protein synthesis or RNA/protein ratio. (4) The gastrocnemius was fractionated into soluble, stromal and myofibrillar proteins. The concentrations and contents of all three proteins were unaltered in cirrhotic animals, compared to controls. (5) It is concluded that in this experimental model of cirrhosis there were no effects on those skeletal muscle variables which are strikingly altered by chronic alcohol feeding.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
6.
7.
Ninety-two nonglaucomatous patients undergoing extracapsular cataract extraction with implantation of a posterior chamber intraocular lens by residents at a Veterans hospital were randomized in double-masked fashion to receive either a topical nonsteroidal antiinflammatory agent, diclofenac sodium 0.1%, or a placebo consisting of vehicle only. One drop of placebo or diclofenac sodium 0.1% was administered on an inpatient basis by trained staff every 6 hours for three doses, starting the afternoon prior to surgery. A further drop was given at 90, 60, 30, and 15 minutes before the operation. Starting 24 hours after surgery, all patients received diclofenac sodium 0.1%. All patients remained hospitalized for 72 hours postoperatively. Mean baseline intraocular pressure (IOP) was 14.0 and 14.1 mm Hg in the diclofenac and placebo groups, respectively. IOP rose 8.6 mm Hg in both groups at 6 hours after surgery. At 24 hours, the mean IOP elevation from baseline was 11.3 mm Hg in the diclofenac group and 9.6 mm Hg in the placebo group (P = .47). Within the first 24 hours, IOP spiked more than 10 mm Hg in 57% (26/46) of the diclofenac patients and in 54% (25/46) of the placebo patients. These results suggest that diclofenac sodium 0.1% drops affect neither the incidence nor the height of IOP elevation following cataract surgery.  相似文献   
8.
A nitroreductase enzyme that has been isolated from Escherichia coli B is capable of bioactivating CB1954 [5-(aziridin-1-yl)-2,4-dinitrobenzamide] to a cytotoxic agent, a property shared with the mammalian enzyme Walker DT diaphorase [NAD(P)H dehydrogenase (quinone), EC 1.6.99.2] as isolated from Walker cells. In contrast to Walker DT diaphorase, which can only reduce the 4-nitro group of CB1954, the E. coli nitroreductase can reduce either (but not both) nitro groups of CB1954 to the corresponding hydroxylamino species. The two hydroxylamino species are formed in equal proportions and at the same rates. CB1954 is reduced much more rapidly by the E. coli nitroreductase than by Walker DT diaphorase. If the reduction of CB1954 was carried out in the presence of V79 cells (which are insensitive to CB1954) a large cytotoxic effect was evident. This cytotoxicity was only observed under conditions in which the E. coli nitroreductase or Walker DT diaphorase reduced the drug. It is proposed that E. coli B nitroreductase would be a suitable enzyme for antibody-directed enzyme prodrug therapy (ADEPT) in combination with CB1954.  相似文献   
9.
Lung disease is a prominent cause of morbidity and mortality worldwide. When a patient has a common lung disease, such as asthma, or a less prevalent one, such as idiopathic pulmonary fibrosis, psychiatric issues should be considered as an integral part of the care plan for each patient. There have been many studies of psychologic factors and psychiatric syndromes in various lung diseases and their treatment. In this article, the authors focus on an evidence-based approach to reviewing this clinical literature.  相似文献   
10.
Pharmacokinetics of a 5-fluorouracil liposomal delivery system.   总被引:3,自引:0,他引:3       下载免费PDF全文
A liposomal delivery system was developed in an attempt to prolong ocular levels of 5-fluorouracil for glaucoma filtering surgery. The pharmacokinetics of the 5-fluorouracil liposomal delivery system were studied in normal pigmented rabbits with 5-fluorouracil labelled with carbon-14 (C-14). 14C 5-fluorouracil was incorporated into the liposomes at a concentration of 10 g/l and injected subconjunctivally in doses of 5 and 10 mg. Concentrations of 5-fluorouracil were assayed at 10 time intervals from 0.5 to 96 hours in cornea, sclera, and conjunctiva and at six time intervals from 0.5 to 12 hours in aqueous. Two peak concentrations were noted at approximately one and eight hours, with measurable levels present at 96 hours. This study demonstrates the ability of this liposomal delivery system to prolong levels of 5-fluorouracial in normal pigmented rabbits.  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