全文获取类型
收费全文 | 3740篇 |
免费 | 170篇 |
国内免费 | 17篇 |
专业分类
耳鼻咽喉 | 20篇 |
儿科学 | 47篇 |
妇产科学 | 36篇 |
基础医学 | 588篇 |
口腔科学 | 139篇 |
临床医学 | 284篇 |
内科学 | 901篇 |
皮肤病学 | 123篇 |
神经病学 | 312篇 |
特种医学 | 60篇 |
外科学 | 497篇 |
综合类 | 15篇 |
预防医学 | 133篇 |
眼科学 | 104篇 |
药学 | 375篇 |
中国医学 | 35篇 |
肿瘤学 | 258篇 |
出版年
2023年 | 19篇 |
2022年 | 37篇 |
2021年 | 68篇 |
2020年 | 29篇 |
2019年 | 46篇 |
2018年 | 70篇 |
2017年 | 55篇 |
2016年 | 59篇 |
2015年 | 60篇 |
2014年 | 68篇 |
2013年 | 98篇 |
2012年 | 166篇 |
2011年 | 186篇 |
2010年 | 93篇 |
2009年 | 76篇 |
2008年 | 154篇 |
2007年 | 193篇 |
2006年 | 193篇 |
2005年 | 206篇 |
2004年 | 197篇 |
2003年 | 191篇 |
2002年 | 181篇 |
2001年 | 124篇 |
2000年 | 136篇 |
1999年 | 112篇 |
1998年 | 53篇 |
1997年 | 33篇 |
1996年 | 43篇 |
1995年 | 32篇 |
1994年 | 39篇 |
1993年 | 29篇 |
1992年 | 83篇 |
1991年 | 80篇 |
1990年 | 59篇 |
1989年 | 69篇 |
1988年 | 60篇 |
1987年 | 41篇 |
1986年 | 47篇 |
1985年 | 43篇 |
1984年 | 51篇 |
1983年 | 24篇 |
1982年 | 31篇 |
1981年 | 21篇 |
1979年 | 32篇 |
1978年 | 25篇 |
1974年 | 18篇 |
1973年 | 21篇 |
1972年 | 18篇 |
1969年 | 18篇 |
1967年 | 20篇 |
排序方式: 共有3927条查询结果,搜索用时 62 毫秒
1.
2.
The efficacy of non-pharmacological intervention for chronic insomnia has been proven by several meta-analytic reviews, an NIH report, an American Academy of Sleep Medicine review, and numerous clinical trials. Behavior therapy for chronic insomnia consists of relaxation, stimulus control, sleep restriction, cognitive restructuring and sleep hygiene education, which has produced reliable and durable changes in total sleep time, sleep onset latency, number and duration of awakening. These studies also showed that the post-treatment effect of behavior therapy is equal to that of hypnotic therapy, and that these effects were maintained for 6 months on follow-up assessment. Elderly insomniac patients would gain considerable benefit from behavioral treatments because there are no adverse physical effects as there are from pharmacological therapy. The authors present the basic theory, techniques of behavior therapy for insomnia, and the results of two important key meta-analytic reviews. Any behavioral approach such as convenient education, self-care enhancement by bibliotherapy, and individual face-to-face counseling, seem to be fruitful not only for American but also Japanese insomnia patients. Nonetheless, there are no currently actual intervention studies using behavior therapy in Japan. We have discussed the methodology of intervention study and published a behavioral self-help manual for people with sleep problems. Development of a behavioral approach to chronic insomnia seemed to be very beneficial and a useful contribution to mental health services. 相似文献
3.
K. Terayama Syuji Toda Nobuhisa Yonemitsu Norimasa Koike Hajime Sugihara 《Virchows Archiv : an international journal of pathology》1997,431(4):291-295
We describe a rare case of papillary carcinoma with extensive proliferation of stromal cells. The stromal cells were immunocytochemically
positive for vimentin, α-smooth muscle actin and desmin, but negative for cytokeratin, epithelial membrane antigen, S-100,
thyroglobulin and CD34. These results and the ultrastructure of the stromal cells, which exhibited the characteristics of
both fibroblasts and smooth muscle cells, indicated an origin from myofibroblasts. We conclude that myofibroblastic proliferation
may contribute to the stromal response in the slow growth of the papillary carcinoma.
Received: 29 August 1996 / 26 May 1997 相似文献
4.
Tetsuo Nagatani Megumi Miyazawa Toshiko Matsuzaki Gaijiro Iemoto Shu-taku Kim Naoko Baba Kanata Miyakawa Hideaki Miyamoto Hiroshi Nakajima Yoshio Hirai 《The Journal of dermatology》1993,20(10):623-629
A 45-year-old man was referred to our department in March of 1989. Physical examination showed erythroderma, palmo-plantar hyperkeratosis, generalized lymphadenopathy, hepatosplenomegaly, and leukemic manifestation. The lymphocyte count in the peripheral blood before treatment was 1.7 × 104 cells/mm3. Atypical lymphocytes such as flower cells and lobulated cells were seen in the peripheral blood. A sample excised from a lymph node showed immunoblastic, pleomorphic T cells by a modified classification scheme of the Working Formulation. A high level of serum LDH was detected (2.1 times the upper normal limit). Anti HTLV-1 antibody was also detected in the serum. The atypical lymphocytes were positive for CD3, CD4, CD5, CD7 and HLA-DR, and negative for CD8. Thus, the clinical, pathologic and immunologic features were those of typical acute-type ATL. The patient was treated with VEPA-M for three months starting in March of 1989. Because of poor response, the patient was then treated with MACOP-B, M-FEPA, and VEPP-B for about one year from June of 1989 and has been free of disease up to the time of writing, March of 1993. 相似文献
5.
The effects of KB-2796, 1-[bis(4-fluorophenyl)methyl]-4-(2,3,4-trimethoxybenzyl)piperazine-2HCl, on the low- and high-voltage activated Ca2+ currents (LVA and HVA ICa, respectively) and on oxidative metabolism were studied in neurons freshly dissociated from rat brain. KB-2796 reduced the peak amplitude of LVA ICa in a concentration-dependent manner with a threshold concentration of 10−7 M when the LVA ICa was elicited every 30 s in the external solution with 10 mM Ca2+. The concentration for half-maximum inhibition (IC50) was 1.9 × 10−6M. At 10−5 M or more of KB-2796, a complete suppression of the LVA ICa was observed in the majority of neurons tested. There was no apparent effect on the current-voltage (I-V) relationship and the current kinetics. KB-2796 delayed the reactivation and enhanced the inactivation of the Ca2+ channel for LVA ICa voltage- and time-dependently, suggesting that KB-2796 preferentially binds to the inactivated Ca2+ channel. KB-2796 at a concentration of3.0 × 10−6M also decreased the peak amplitude of the HVA ICa without shifting the I-V relationship. In addition, KB-2796 reduced the oxidative metabolism (the formation of reactive oxygen species) of the neuron in a concentration-dependent manner with a threshold concentration of3 × 10−6M. It is suggested that the inhibitory action of KB-2796 on the neuronal Ca2+ influx and the oxidative metabolism, in combination with a cerebral vasodilatory action, may reduce ischemic brain damage. 相似文献
6.
Tomoko FUKUNAGA Satoshi UKAI Toshiko KOBAYASHI Tsuyoshi NISHIMURA Masatoshi TAKEDA 《Psychogeriatrics》2006,6(4):159-167
Background: Progression of the core and accessory symptoms of dementia can be slowed if drug therapies and psychosocial interventions are administered at an early stage. The aim of this study was to develop and standardize a neuropsychological test for the elderly that can detect dementia at an early stage with high sensitivity and can evaluate a wide range of severities of dementia based on assessments of various cognitive functions. Methods: A preliminary test consisting of 23 items and the Nishimura Mental State Scale for the Elderly (NM Scale), which evaluates the mental functions of elderly individuals by observing their actual behaviors in daily life, were administered to 448 elderly subjects. After applying Hayashi’s quantification theory type I to the results, we revised the preliminary test to construct a neuropsychological test for the elderly, which we named the Nishimura Dementia Test (ND Test), and standardized it. Then, we examined its validity and test–retest reliability. Results: Among the 448 subjects, there was a strong correlation between the ND Test scores and NM Scale scores. The ND Test showed a good general agreement rate for the discrimination of the severity of dementia, and good sensitivity and specificity of discrimination of dementia when compared with the actual NM Scale. Using different groups of elderly subjects, the ND Test showed validity and test–retest reliability, and the ND Test scores showed strong correlations with the Revised Hasegawa Dementia Scale scores and the Mini‐Mental State Examination scores. Conclusions: The ND Test is based on assessment of a variety of cognitive functions and can evaluate a wide range of severities of dementia with good validity and reliability. 相似文献
7.
Selective necrosis in hamster pancreatic tumours using photodynamic therapy with phthalocyanine photosensitization. 总被引:3,自引:0,他引:3
P T Chatlani P J Nuutinen N Toda H Barr A J MacRobert J Bedwell S G Bown 《The British journal of surgery》1992,79(8):786-790
Photodynamic therapy (PDT) is often thought to be able to effect selective tumour necrosis. This therapeutic selectivity, based on transient differences in tumour: normal tissue photosensitizer concentration ratios, is rarely useful clinically in extracranial tumours, although PDT itself may be of value by virtue of the nature of the damage produced and healing of normal tissue by regeneration. This report describes the effects of PDT on normal pancreas and chemically induced pancreatic cancers in the hamster, where a different mechanism of selective necrosis may be seen. Photosensitizer distribution in normal and neoplastic pancreas was studied by chemical extraction and fluorescence microscopy. Correlation of distribution studies with necrosis produced by PDT shows that the photodynamic dose (product of tissue concentration of sensitizer and light dose) threshold for damage is seven times as high for normal pancreas as for pancreatic cancer. Tumour necrosis extended to the point where tumour was invading normal areas without damaging the normal tissue. In rat colonic cancer, photodynamic dose thresholds in tumour and normal tissue are similar and so such marked selectivity of necrosis is not possible. The reason for this selectivity in the pancreas is not clear, but recent evidence has suggested a difference in response to PDT between normal and neoplastic pancreatic cell lines and the presence of a singlet oxygen scavenger in normal pancreas is postulated. Furthermore, the present fluorescence microscopy studies suggest that tumour stroma contains the highest level of photosensitizer and thus receives the highest photodynamic dose during PDT. These results suggest a possible role for PDT in treating small pancreatic tumours or as an adjuvant to other techniques, such as surgery, that reduce the main bulk of tumours localized to the pancreas. 相似文献
8.
AIMS: Differential diagnosis of allergic conjunctivitis or dry eye is sometimes very difficult to diagnose by symptoms and clinical examination alone, especially in older patients. It was hypothesised that clinically allergic patients who were serum antigen specific IgE negative were candidates for dry eye. METHODS: Sixty patients were studied prospectively who were clinically diagnosed with allergic conjunctivitis by their itchy sensation and papilla formation of conjunctiva. They consisted of 30 serum antigen specific IgE positive and 30 IgE negative patients, with no significant differences in age. Dry eye examination and serum total IgE were performed on these two groups. RESULTS: No significant differences were seen between the two groups with regard to age (p = 0.76) and sex ratio. The antibody negative group had lower Schirmer's test scores (p = 0.002), lower tear clearance (p = 0.0001), lower tear function index (p = 0.0001), and lower serum total IgE (p = 0.04) than the antibody positive group. CONCLUSION: This study suggests that the evaluation of serum antigen specific IgE and tear dynamics are important for the differential diagnosis of patients with allergic conjunctivitis and dry eye. Clinically diagnosed allergic conjunctivitis with negative serum antigen specific and total IgE can be one form of dry eye. 相似文献
9.
Abstract Nitric oxide (NO) plays an important physiological role in regulating gastrointestinal motility. Involvement of endogenous NO was evaluated in the response to non-adrenergic, non-cholinergic (NANC) nerve stimulation of the dog sphincter muscle of Oddi. Transmural electrical stimulation (TES), nicotine (10?5M) and K+ (10 mM) produced only a relaxation in the sphincter muscle strips contracted with substance P, which was not potentiated by atropine. The TES-induced relaxation was abolished by tetrodotoxin (3 times 10?7 M) and oxyhaemoglobin (1.6 times 10?5 M), but not affected by atropine (10?7 M), propranolol (10?7 M), phentolamine (10?7 M), indomethacin (10?6 M), chole-cystokinin (CCK, 10?8 M) and vasoactive intestinal polypeptide (VIP, 10?8 M). The relaxation was also abolished by treatment with NG-nitro-L-arginine (L-NA, 10?5 M), an NO synthase inhibitor. Nicotine produced a transient relaxation, which was abolished by tetrodotoxin, hexamethonium (10?5 M) and L-NA, but not affected by atropine and NG-nitro-D-arginine (D-NA, 10?5 M). The addition of K+ elicited a transient relaxation, which was abolished by tetrodotoxin and L-NA. The inhibitory effects of L-NA were antagonized by L-arginine (10?3 M). The presence of neurons containing nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase was histochemically demonstrated in the sphincter of Oddi. These findings may indicate that TES, nicotine and K+ liberate NO from NANC inhibitory nerve which is involved in the relaxation of the dog sphincter of Oddi. The muscular tone does not seem to be regulated by cholinergic nerves under the experimental conditions used. 相似文献