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   183936篇
  免费   1441篇
  国内免费   30篇
耳鼻咽喉   1242篇
儿科学   6900篇
妇产科学   3177篇
基础医学   17558篇
口腔科学   1806篇
临床医学   13215篇
内科学   32387篇
皮肤病学   742篇
神经病学   17375篇
特种医学   9138篇
外科学   29969篇
综合类   2352篇
一般理论   6篇
预防医学   18790篇
眼科学   2907篇
药学   10133篇
中国医学   644篇
肿瘤学   17066篇
  2023年   45篇
  2022年   78篇
  2021年   146篇
  2020年   144篇
  2019年   191篇
  2018年   22108篇
  2017年   17515篇
  2016年   19678篇
  2015年   1102篇
  2014年   1050篇
  2013年   1244篇
  2012年   7505篇
  2011年   21535篇
  2010年   19099篇
  2009年   11808篇
  2008年   19993篇
  2007年   22198篇
  2006年   1093篇
  2005年   2674篇
  2004年   3849篇
  2003年   4798篇
  2002年   2936篇
  2001年   360篇
  2000年   456篇
  1999年   252篇
  1998年   308篇
  1997年   306篇
  1996年   183篇
  1995年   206篇
  1994年   184篇
  1993年   148篇
  1992年   104篇
  1991年   170篇
  1990年   180篇
  1989年   135篇
  1988年   104篇
  1987年   84篇
  1986年   68篇
  1985年   101篇
  1984年   99篇
  1983年   74篇
  1982年   106篇
  1981年   73篇
  1980年   77篇
  1978年   45篇
  1977年   54篇
  1974年   48篇
  1938年   60篇
  1932年   59篇
  1930年   46篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.

Background  

Colorectal cancer, if detected early, has greater than 90% 5-year survival. However, survival has been shown to vary across racial/ethnic groups in the United States, despite the availability of early detection methods.  相似文献   
92.
Pituitary metastases of solid tumours are infrequent, specially as a first manifestation. When they happen, they are usually due to breast or lung cancer and are asymptomatic or produce diabetes insipidus. It is very strange that they produce hormonal deficiency. We present a case report of a bronchogenic adenocarcinoma in a 65-year-old man which began with panhypopituitarism, diabetes insipidus and visual alterations. Magnetic resonance imaging revealed a large sellar mass, with clivus infiltration and invading the right cavernous sinus. The biopsy result was adenocarcinoma metastases from lung cancer.  相似文献   
93.
BACKGROUND: The role of large colony streptococci groups C or G as pathogen agents in sore throat has been questioned. AIM: To analyse clinical features of patients with large colony streptococci groups C or G compared with patients with group A streptococci (GAS) and with negative cultures. DESIGN OF STUDY: Prospective study of patients with sore throat. SETTING: Two Norwegian general practices in Stokke and Kongsberg communities with 6500 patients.METHOD: Frequency of clinical features in the three patient categories including the four Centor criteria (fever, anterior cervical lymphadenopathy, tonsillar exudates, and lack of cough), degree of pain on swallowing, pharyngeal rubor, C-reactive protein (CRP) values, patient age between 3 and 14 years, and duration of symptoms before seeing the doctor. A logistic regression analysis to find independent predictors was performed. RESULTS: Out of 306 patients with a sore throat, 244 were adults and 62 were children under 10 years old; 40% were men. One hundred and twenty-seven had GAS, 33 had streptococci groups C or G, and 146 had negative throat cultures. Forty-eight per cent of the GAS patients and 45% of the C or G patients met three or four of the Centor criteria. The logistic regression revealed that in patients with GAS considerable pain on swallowing, an age of 3-14 years and a duration of symptoms of < or =3 days or less were significantly associated with GAS infection in addition to the Centor criteria. The same results were found when all streptococci were analysed together, in addition elevated CRP was significant. In patients with streptococci group C or G an elevated CRP-value was significantly associated. CONCLUSION: Patients with tonsillitis caused by streptococcus groups C or G have, to a large extent, the same clinical picture as patients with GAS. Large colony streptococci groups C and G should be considered as throat pathogens in line with GAS.  相似文献   
94.
Background. Accepted practices of informed consent often result in suboptimal patient understanding of research studies.Methods. This pilot study aimed to assess trial-specific tailored materials, compared to a widely used generic booklet about clinical trials, randomly assigned to 118 candidates for cancer clinical trials. Study outcomes were: satisfaction with decision-making; satisfaction with materials; and subjective understanding of the clinical trial.Results. There were no major differences between groups. Participants rated tailored materials higher as a useful reference.Conclusions. Trial-specific materials hold utility for reference during clinical trials. Studies of informed consent are feasible, although important factors limit research.  相似文献   
95.
Several single agonist/antagonist primary muscle spindle afferents were simultaneously recorded in chloralose anaesthetized cats. It was shown that their dynamic and static sensitivity to sinusoidal muscle stretches could be increased or decreased via the fusimotor system by extension and flexion of the contralateral hind limb as well as by stretch of ipsilateral muscles and stimulation of ipsilateral skin nerves. The results seem to support the hypothesis that the primary muscle spindle afferents convey complex multisensory messages to the central nervous system (CNS).  相似文献   
96.
The leaf essential oil of Eugenia zuchowskiae from Monteverde, Costa Rica, has been obtained by hydrodistillation and analyzed by GC–MS. The principal constituents of E. zuchowskiae leaf oil were α-pinene (28.3%), β-caryophyllene (13.2%), α-humulene (13.1%), and α-copaene (8.1%). The leaf essential oil of E. zuchowskiae showed pronounced in-vitro cytotoxic activity against MCF-7, MDA-MB-468, and UACC-257 human tumor cell lines. The major components showed cytotoxic activities comparable to doxorubicin (LC50 14–70 μg/ml).  相似文献   
97.
98.
99.
100.
The D2-dopamine receptor antagonist raclopride was administered to eight healthy male subjects, who had previously experienced akathisia following antipsychotic drugs. The influence of administration rate on onset, severity and duration of akathisia and on prolactin response was studied. Raclopride 3,5 or 9 mg or placebo (P) was administered as single IV infusions during 10 min (R10 min/3 mg), 1 h (R1h/5 mg) or 4 h (R4h/9 mg) according to a randomized double-blind design. Despite a 24-fold difference in administration rate a similar peak raclopride concentration of about 350 nmol/l was obtained after all three infusions. Three of the eight subjects experienced akathisia following R10 min/3 mg and R1h/5 mg, respectively. After R4h/9 mg seven subjects experienced akathisia of longer duration but not more severe than after the short infusions. The incidence and duration of akathisia seem to be mainly related to the plasma raclopride concentrations over time, whereas the rate of administration might be more important for the severity. A maximal prolactin response was induced which was not markedly affected by the rate of administration.  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