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   25467篇
  免费   1952篇
  国内免费   67篇
耳鼻咽喉   211篇
儿科学   739篇
妇产科学   691篇
基础医学   3589篇
口腔科学   445篇
临床医学   2966篇
内科学   5017篇
皮肤病学   388篇
神经病学   2615篇
特种医学   1298篇
外科学   2733篇
综合类   230篇
现状与发展   1篇
一般理论   24篇
预防医学   2471篇
眼科学   403篇
药学   1837篇
中国医学   58篇
肿瘤学   1770篇
  2023年   278篇
  2022年   441篇
  2021年   795篇
  2020年   561篇
  2019年   858篇
  2018年   859篇
  2017年   686篇
  2016年   684篇
  2015年   752篇
  2014年   980篇
  2013年   1289篇
  2012年   2003篇
  2011年   2017篇
  2010年   1067篇
  2009年   1020篇
  2008年   1621篇
  2007年   1610篇
  2006年   1421篇
  2005年   1429篇
  2004年   1265篇
  2003年   1068篇
  2002年   1012篇
  2001年   343篇
  2000年   257篇
  1999年   279篇
  1998年   197篇
  1997年   194篇
  1996年   128篇
  1995年   111篇
  1994年   114篇
  1993年   89篇
  1992年   157篇
  1991年   122篇
  1990年   145篇
  1989年   121篇
  1988年   116篇
  1987年   111篇
  1986年   106篇
  1985年   111篇
  1984年   86篇
  1983年   70篇
  1982年   73篇
  1981年   61篇
  1980年   44篇
  1979年   64篇
  1978年   48篇
  1977年   39篇
  1974年   40篇
  1973年   37篇
  1972年   37篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
71.
The Proxemics/Activity test and the Eat/Drink test, two components of the Anxiety/Defense Test Battery, were developed to measure defensive reactions to situations associated with a natural predator (cat). In the present studies the behavioral effects of 8-OH-DPAT treatment (0.01–1.0 mg/kg, SC) were entirely consistent with anxiety/fear reduction. These effects included an increase in time spent near the cat compartment, and a complimentary decrease in time spent farthest from this compartment, together with an increase in transits and locomote behavior. 8-OH-DPAT (1.0 mg/kg) also increased eat frequencies and durations (highly preferred food) both during and following cat presentation, without influencing drinking. This finding is discussed with reference to previous findings with 8-OH-DPAT in studies assessing both food intake and anxiolysis. Interestingly, 8-OH-DPAT was more potent in a majority of its effects in female subjects, a finding consistent with recent neurochemical data. These findings provide important behavioral evidence for a sexual differentiation in 5-HT function, and support the case for greater emphasis on female subjects in animal models of anxiety.Supported by NIH MH42803 and RCMI Grants RR03061 and RR01825  相似文献   
72.
Acquired Loss of Red-Cell Wj Antigen in a Patient with Hodgkin''s Disease   总被引:2,自引:0,他引:2  
A patient with Hodgkin's disease became temporarily Wj-negative with alloanti-Wj in his serum. Four human autoantibodies, and 1 of 2 murine monoclonal antibodies, with serological characteristics of anti-Wj were nonreactive with his red cells, confirming that they have anti-Wj specificity. Six siblings of the patient are all Wj-positive. The patient was also temporarily Anton-negative, and cross-testing between Wj and Anton red cells and antisera showed mutual compatibility, indicating that the antigens are the same. The patient and 3 of his 6 siblings are also of the rare Lu: - 13 phenotype, providing the first evidence that this is an inherited characteristic.  相似文献   
73.
The performance of a lateral-flow immunoassay, the QuickVue Influenza Test, for detection of influenza A and B viruses in comparison with that of cell culture was evaluated by using nasopharyngeal aspirates, in viral transport medium, from children with respiratory tract infections. The sensitivity and specificity were 79.2 and 82.6%, respectively.  相似文献   
74.
75.
This article highlights positive outcomes for a convenience sample of six women (49-64 years of age) with fibromyalgia syndrome (FMS) who participated in an exercise program over 5 years. This group showed improvement with various FMS symptoms,fitness, and psychosocial factors early in the program, then showed further improvement as a result of adding new exercises to the protocol during the fourth and fifth years. Data suggest that certain people with FMS can improve their functional capacity with exercise over time, and move to even higher levels of physical function while aging and coping with FMS. Practical advice is provided for rehabilitation nurses regarding exercise and FMS.  相似文献   
76.
Acute hypertensive responses during nitrous oxide-opioid-relaxant anesthesia are a common clinical problem. In adult men undergoing radical prostatectomy procedures and anesthetized with a standardized technique, we evaluated the effectiveness of alfentanil, isoflurane, and trimethaphan in treating acute hemodynamic and stress hormone responses to surgical stimulation. Stress hormone concentrations were measured 1 min before skin incision, after the onset of an acute hypertensive response, and after returning the mean arterial pressure to within 10% of the preincision values with one of the three treatment modalities. Pretreatment plasma alfentanil concentrations (151 +/- 47 to 156 +/- 47 ng.ml-1) and end-tidal nitrous oxide concentrations (66 +/- 2 to 68 +/- 2%) were similar in all three groups. Acute hypertensive events were associated with significantly increased concentrations of catecholamines and vasopressin (antidiuretic hormone [ADH]). Whereas intravenous alfentanil returned all hormone concentrations to preincision values, norepinephrine and glucose concentrations were significantly increased after adjunctive isoflurane administration. Although trimethaphan decreased the norepinephrine concentration, the epinephrine, beta-endorphin, cortisol, ADH, and glucose concentrations were significantly increased compared to preincision values. However, the persistent elevation in the posttreatment ADH concentration in the trimethaphan group was the only significant difference between the three groups. Mean (+/- standard deviation) times to awakening (2.8 +/- 3.3 to 3.8 +/- 4.2 min), extubation (8.1 +/- 4.8 to 10.3 +/- 8.5 min), and orientation (19.6 +/- 20.4 to 24.6 +/- 19.1 min) were similar in all three groups. Naloxone was required more frequently in patients in the alfentanil (35%) and isoflurane (24%) groups than in the trimethaphan group (4%).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
77.
Image quality and safety of magnetic resonance (MR) imaging were evaluated in vitro and in eight patients with the most commonly employed metallic biliary endoprosthesis. In vitro, the stent produced no tip deflection at 0.6 or 1.5 T. Trace magnetic susceptibility artifact, similar to artifact from a column of air, paralleled the stent. In patients, image degradation was minimal with conventional pulse sequences. Middle-field-strength spin-echo images revealed minimal artifacts indistinguishable from those produced by pneumobilia.  相似文献   
78.
79.
Electrical stimulation of four specific acupuncture points (Liver 3, Stomach 36, Large Intestine 11, and the Groove for Lowering Blood Pressure) was examined in order to determine the effect of this stimulation on diastolic blood pressure in 10 subjects with diastolic hypertension. Subjects were randomly divided into two groups: (1) an Acu-ES group, which received electrical stimulation applied to the four antihypertensive acupuncture points, and (2) a Sham-ES group, which received electrical stimulation applied to non-acupuncture-point areas. A repeated-measures analysis of variance revealed a significant, immediate poststimulation reduction of diastolic blood pressure for the Acu-Es group versus the Sham-ES group. Further studies are needed to determine whether there are other acupuncture points, stimulation characteristics, or modalities that can enhance this treatment effect and whether the treatment effect can last for a clinically significant period of time.  相似文献   
80.
High-specificity in-situ hybridization. Methods and application.   总被引:2,自引:0,他引:2  
We describe a technique of in-situ hybridization using oligonucleotide probes employing the expression of immunoglobulin VH genes as a model. Optimal conditions for hybridization with the 35S-labeled oligonucleotide probes were established with monoclonal B-cell lines that express VH genes of known nucleic acid sequence. The range of sensitivity and specificity achieved with this technique is documented. Under conditions of high stringency, this method can detect the expression of highly related VH hypervariable regions.  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