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   3928篇
  免费   274篇
  国内免费   22篇
耳鼻咽喉   66篇
儿科学   76篇
妇产科学   52篇
基础医学   468篇
口腔科学   113篇
临床医学   366篇
内科学   948篇
皮肤病学   84篇
神经病学   126篇
特种医学   134篇
外科学   419篇
综合类   126篇
一般理论   2篇
预防医学   348篇
眼科学   78篇
药学   484篇
  4篇
中国医学   74篇
肿瘤学   256篇
  2024年   22篇
  2023年   74篇
  2022年   237篇
  2021年   336篇
  2020年   178篇
  2019年   170篇
  2018年   216篇
  2017年   140篇
  2016年   161篇
  2015年   155篇
  2014年   202篇
  2013年   208篇
  2012年   346篇
  2011年   344篇
  2010年   186篇
  2009年   146篇
  2008年   169篇
  2007年   144篇
  2006年   160篇
  2005年   130篇
  2004年   123篇
  2003年   91篇
  2002年   68篇
  2001年   20篇
  2000年   26篇
  1999年   23篇
  1998年   11篇
  1997年   12篇
  1996年   11篇
  1995年   10篇
  1994年   10篇
  1993年   8篇
  1992年   11篇
  1991年   6篇
  1990年   7篇
  1989年   6篇
  1988年   8篇
  1987年   4篇
  1985年   3篇
  1984年   4篇
  1983年   4篇
  1982年   2篇
  1981年   4篇
  1979年   6篇
  1975年   2篇
  1972年   2篇
  1935年   1篇
  1931年   1篇
  1929年   1篇
  1923年   2篇
排序方式: 共有4224条查询结果,搜索用时 0 毫秒
91.
92.
Human amniotic membrane as a homograft material was compared to temporalis fascia to close tympanic membrane perforations in 50 patients with chronic otitis media. Human amniotic membrane was used in 20 patients while temporalis fascia was used in the remaining 30. Anatomical closure of the perforation and reduction of the air-bone gap was measured. The graft uptake showed a 65% success rate for the amniotic membrane and 56.7% for the temporalis fascia at 3 months post-operatively. Significant closure of air-bone gap was observed in the human amniotic group. These results indicate comparable outcomes between human amniotic membrane and the temporalis fascia graft.  相似文献   
93.
Flavonoids are known to possess cardioprotective properties. Vascular endothelial function is a surrogate marker for cardiovascular diseases, including hypertension. We have studied the effects of chronic flavonoid treatment on vascular endothelial functions in spontaneously hypertensive rats (SHR). Starting from 6-7 weeks old, SHR were given flavonoids (baicalein, flavone, or quercetin) orally (10 mg/kg, once daily) to the SHRs for 4 weeks. Aortas from all the flavonoid-treated animals showed remarkably higher endothelium-dependent relaxations to acetylcholine, to a similar extent as those pretreated with the angiotensin-converting enzyme inhibitor, captopril. However, in contrast to other experimental groups, flavone pretreatment also enhanced the endothelium-independent relaxations to sodium nitroprusside. In addition, treatment with either flavone or quercetin induced a significant attenuation in systolic blood pressure of the hypertensive animals. The present results suggest that chronic treatment with the flavonoids (baicalein, flavone, and quercetin) preserves vascular endothelial functions in hypertensive animals through several possible actions, including increasing endothelial nitric oxide production and bioavailability and reduction in blood pressure.  相似文献   
94.
Quality of margarine: fats selection and processing parameters   总被引:1,自引:0,他引:1  
Optimum processing conditions on palm oil-based formulations are required to produce the desired quality margarine. As oils and fats contribute to the overall property of the margarine, this paper will review the importance of beta' tending oils and fats in margarine formulation, effects of the processing parameters -- emulsion temperature, flow-rate, product temperature and pin-worker speed -- on palm oil margarines produced and their subsequent behaviour in storage. Palm oil, which contributes the beta' crystal polymorph and the best alternative to hydrogenated liquid fats, and the processing conditions can affect the margarine consistency by influencing the solid fat content (SFC) and the types of crystal polymorph formed during production as well as in storage. Palm oil, or hydrogenated palm oil and olein, in mixture with oils of beta tending, can veer the product to the beta' crystal form. However, merely having beta' crystal tending oils is not sufficient as the processing conditions are also important. The emulsion temperature had no significant effect on the consistency and polymorphic changes of the product during storage, even though differences were observed during processing. The consistency of margarine during storage was high at low emulsion flow-rates and low at high flow rates. The temperature of the scraped-surface tube-cooler is the most important parameter in margarine processing. High temperature will produce a hardened product with formation of beta-crystals during storage. The speed of the pin-worker is responsible for inducing crystallization but, at the same time, destroys the crystal agglomerates, resulting in melting.  相似文献   
95.
It is common practice in therapeutic trials in Acute Lymphoblastic Leukaemia (ALL) to treat chemotherapy induced toxicities. In this study, 50 newly diagnosed ALL patients were enrolled and the median age was 14.5 years. 32 patients were male and 18 female. Prognostic factors were analysed. Remission induction, consolidation and maintenance therapy with conventional combination chemotherapy and CNS prophylaxis with intrathecal methotrexate and radiotherapy were instituted to all patients for long term event free survival. Results of induction therapy and overall outcomes of treatment were observed. Chemotherapy induced toxicities were also detected and treated accordingly. These toxicities were described in 4 groups depending on the frequency of their development in chemotherapy received patients. Haematological and gastrointestinal side effects and alopecia were expected i.e., developed in >75% of patients. Prednisolone and vincristine induced toxicities were common i.e., observed in >25% of patients. Hepatic complications and anthracycline induced tachycardia were occasional i.e., occurred in <25% and localized phlebitis and/ or soft tissue necrosis were rare and accidental i.e., developed in 5% of patients.  相似文献   
96.
A laboratory-scale study of bioconversion of local lignocellulosic material, oil palm biomass (OPB) was conducted by evaluating the enzyme production through microbial treatment in solid state bioconversion (SSB). OPB in the form of empty fruit bunches (EFB) was used as a solid substrate and treated with the white-rot fungus, Phanerochaete chrysosporium, to produce ligninase. The results showed that the highest ligninase activity of 400.27 U/liter was obtained at day 12 of fermentation. While the optimum study indicated the enzyme production of 1472.8 U/liter with moisture content of 50%, 578.7 U/liter with 10% v/w of inoculum size, and 721.8 U/liter with co-substrate concentration of 1% (w/w) at days 9, 9 and 12 of fungal treatment, respectively. The parameters glucosamine and reducing sugar were observed to evaluate the growth and substrate utilization in the experiment.  相似文献   
97.
Dengue is the most common and widespread arthropod borne arboviral infection in the world today. It is estimated that there are at least 100 million cases of dengue fever (DF) annually and 500,000 cases of dengue hemorrhagic fever (DHF) which require hospitalization. In Malaysia, it has become a major public health problem. Malaysia recorded 19,544 dengue cases in 1997, the highest recorded since the disease was made notifiable in the country. Of 19,544 cases, 806 were DHF with 50 deaths. The objectives of this analysis were to describe the incidence of dengue fever and dengue hemorrhagic fever in Kota Bharu, Kelantan, Malaysia for the years 1998-2003 and to explore the characteristics of dengue fever and dengue hemorrhagic fever in Kota Bharu, Kelantan, Malaysia for years 1998-2003. A total of 4,716 dengue cases were notified involving 4,476 (94.9%) DF and 240 (5.1%) DHF cases, which increased though the years. The highest incidence was in January (701 or 14.9%), while the lowest was in May (188 or 4.0%). Forty percent of cases (n=1,890) were in the 15-29 year old group. The Majority were Malays (4,062 or 86.1%) and 2,602 or 55.2% were male. A total of 4,477 cases (95%) were local cases and 4,289 or 91% came from the urban area. For priority areas, 3,772 (80%) were from priority 1. More than half the cases had positive serology results. All symptoms occurred in more than 96% of cases and fever was the commonest (99.7%). The mean values for age, temperature, systolic and diastolic blood pressure (BP) were 27.8 +/- 15.4 years, 37.9 +/- 0.90 degrees C, 115 +/- 15.2 mmHg and 73 +/- 11.1 mmHg, respectively. The mean value for the time interval between the onset of symptoms and diagnosis, onset of symptoms and notification and time of diagnosis to notification were 5.1 +/- 2.3, 5.9 +/- 2.5 and 0.8 +/- 1.1 days, respectively. There were associations between the types of dengue and classification, area and priority area. Among the symptoms, the association was only seen in joint pain. The mean significant differences between DF and DHF were found in age and systolic blood pressure. The incidence of dengue in Kota Bharu is comparable to that in Malaysia. The increase in the number of cases needs to be addressed promptly with effective surveillance, prevention and control programs.  相似文献   
98.
The effect of the antineoplastic immunosuppressive alkylating agent cyclophosphamide (CPhA) on the modification of the carcinogen-metabolizing capacity was studied in vivo in mouse liver microsomes at different durations of treatment, from one to six consecutive days. The in vitro effect of increasing concentrations of the drug upon this enzyme system was also investigated. Following the administration of CPhA, a significant time-dependent decrease was observed in the activity of the low substrate level of the hepatic microsomal N-nitrosodimethylamine demethylase (NDMAdII). The high substrate level of the enzyme (NDMAdII) also exhibited a similar decrease which was not a subject for the treatment intervals where the greatest decrease (-60%; p<0.05) emerged at day 3 of the administration-point. The activity of the aryl hydrocarbon (benzo(alpha)pyrene) hydroxylase (AHH) revealed a significant increase at the single dose of CPhA, while at the repeated dose treatment (for 3 days) no alteration was noticed in the enzyme activity. This figure of expression in AHH was reversed to a significant inhibition at the 6 day-repeated dose, the time-point at which an almost identical effect was also observed in the hepatic content of cytochrome P450. The alterations in the metabolism of NDMA and benzo(alpha)pyrene which had been seen in the in vivo assays was further confirmed by the results of the in vitro experiment.  相似文献   
99.
100.
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