全文获取类型
收费全文 | 2616篇 |
免费 | 147篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 92篇 |
妇产科学 | 13篇 |
基础医学 | 364篇 |
口腔科学 | 78篇 |
临床医学 | 160篇 |
内科学 | 700篇 |
皮肤病学 | 25篇 |
神经病学 | 132篇 |
特种医学 | 129篇 |
外科学 | 481篇 |
综合类 | 8篇 |
预防医学 | 94篇 |
眼科学 | 27篇 |
药学 | 172篇 |
中国医学 | 3篇 |
肿瘤学 | 285篇 |
出版年
2023年 | 44篇 |
2022年 | 76篇 |
2021年 | 115篇 |
2020年 | 62篇 |
2019年 | 69篇 |
2018年 | 75篇 |
2017年 | 50篇 |
2016年 | 67篇 |
2015年 | 69篇 |
2014年 | 78篇 |
2013年 | 86篇 |
2012年 | 124篇 |
2011年 | 159篇 |
2010年 | 95篇 |
2009年 | 70篇 |
2008年 | 97篇 |
2007年 | 95篇 |
2006年 | 86篇 |
2005年 | 112篇 |
2004年 | 117篇 |
2003年 | 107篇 |
2002年 | 116篇 |
2001年 | 66篇 |
2000年 | 61篇 |
1999年 | 57篇 |
1998年 | 33篇 |
1997年 | 26篇 |
1996年 | 26篇 |
1995年 | 25篇 |
1994年 | 27篇 |
1993年 | 17篇 |
1992年 | 39篇 |
1991年 | 24篇 |
1990年 | 35篇 |
1989年 | 41篇 |
1988年 | 37篇 |
1987年 | 24篇 |
1986年 | 37篇 |
1985年 | 24篇 |
1984年 | 20篇 |
1983年 | 15篇 |
1981年 | 11篇 |
1980年 | 11篇 |
1979年 | 11篇 |
1976年 | 13篇 |
1975年 | 13篇 |
1974年 | 12篇 |
1970年 | 13篇 |
1969年 | 16篇 |
1967年 | 10篇 |
排序方式: 共有2773条查询结果,搜索用时 0 毫秒
21.
T. Tsuji P. Shrestha K. Yamada H. Takagi F. Shinozaki K. Sasaki K. Maeda M. Mori 《Virchows Archiv : an international journal of pathology》1992,420(5):377-383
Summary Proliferating cell nuclear antigen (PCNA) is a nuclear protein synthesized in the late G1 and S phase of the cell cycle and immunohistochemical detection of the protein represents a useful marker for the proliferating fraction of cells in tissue specimens. A series of malignant and pre-malignant lesions of the oral cavity and skin were evaluated by the streptavidin biotin immunoperoxidase method for detection of this protein. Monoclonal anti-PCNA antibody (PC 10) labelled proliferating cells in all cases with varying intensity of nuclear staining. In squamous cell carcinoma (n=48), PCNA positivity correlated with the differentiation and atypia of the tumour cells; however, in poorly differentiated tumours, the relationship between PCNA expression and proliferation was lost. Basal cell carcinoma showed an increased growth fraction in tiny epithelial nests (mean 43.8, SD 6.0,n=20) than in neoplastic basal cells (mean 30.1, SD 6.9,n=8). The growth fractions were significantly higher in the pre-malignant lesions (leukoplakia, mean 22.3, SD 7.7,n=14; Bowen's disease, mean 45.2, SD 11.7,n=12; senile keratosis, mean 41.2, SD 7.0,n=12) than in the normal mucosa (mean 9.8, SD 4.9,n=10), suggesting that cellular growth fractions correlate with the degree of dysplasia in pre-malignant lesions. 相似文献
22.
Shohei Inoue Yoshihisa Yokota Norimasa Yoshida Teiji Tsuruta 《Macromolecular chemistry and physics.》1966,90(1):131-138
The system diethylzinc/optically active alcohol was examined as catalyst for asymmetric-selective polymerization of propylene oxide. Optically active alcohols with rigid structure are effective for the asymmetric selection. D (–)-1-Methoxypropanol-2 as well as poly(D -propylene oxide) of low molecular weight with hydroxyl end groups select L (–)-propylene oxide. ?Catalyst control”? mechanism of the stereoselection in the polymerization is suggested on this and other bases. 相似文献
23.
Masayuki Yokoyama Hayato Anazawa Akeo Takahashi Shohei Inoue Kazunori Kataoka Nobuhiko Yui Yasuhisa Sakurai 《Macromolecular chemistry and physics.》1990,191(2):301-311
Novel segmented multiblock copolymers ( 7 ) were synthesized by linking poly(ethylene oxide) (PEO) blocks with poly(β-benzyl L -aspartate)(PBLA) blocks via urethane and urea bonds, which were formed by the reaction of 4,4′-methylenediphenyl isocyanate ( 5 ) with the terminal hydroxyl groups of α-hydro-ω-hydroxypoly(oxyethylene) ( 4 ) and the terminal amino groups of poly(β-benzyl L -aspartate)-block-iminohexamethyleneimino-block-poly(β-benzyl L -aspartate) ( 3 ) [prepared from 1,6-hexanediamine ( 1 ) and β-benzyl L -aspartate N-carboxy anhydride ( 2 )], respectively. Membranes with various water contents were obtained from these copolymers by changing the lengths of the PEO and PBLA segments. The study of the permeation of 1-phenyl-1,2-ethanediol, vitamin B12 and myoglobin through the membranes showed a high dependency of the permeability on the molecular weight of the solutes. 相似文献
24.
25.
Michio Yoneyama Shohei Inoue Teiji Tsuruta 《Macromolecular chemistry and physics.》1967,107(1):241-245
During thermal degradation of poly(vinyl chloride) in a nitrogen atmosphere polyene sequences of different lengths are formed by dehydrochlorination. The distribution of the sequence lengths in the polymer is approximated by analysis of the electron spectra, and the spectroscopically determined polyene content is compared with the amount of hydrogen chloride split off. With increasing temperature, as well as with increasing time of degradation, the distribution of the polyene sequence lengths shifts towards shorter sequences. In contrast to degraded poly(vinyl chloride) powder, degraded poly(vinyl chloride) foils exhibit a marked shift towards longer sequences. Vinylisobutyl ether as comonomer unit in the polymer chains effects a considerable shift of the sequence lengths distribution towards shorter polyene sequences. The spectroscopically determined polyene content agrees with the amount of liberated hydrogen chloride only a t very low conversions while with increasing dehydrochlorination a growing polyene deficit is found. Therefore, it is to be concluded that polyene sequences are consumed by consecutive reactions in which primarily the longer polyene sequences are involved. A further conclusion that may be drawn from these experiments is that the formation of long polyene sequences takes place very rapidly once the initial step of dehydrochlorination has occurred at a labile site. Apart from the above mentioned consecutive reactions, only the number, not the average length, of the polyene sequences changes substantially with increasing time of degradation. 相似文献
26.
We identified dish-based dietary patterns for breakfast, lunch, and dinner and assessed the diet quality of each pattern. Dietary data were obtained from 392 Japanese adults aged 20–69 years in 2013, using a 4 d dietary record. K-means cluster analysis was conducted based on the amount of each dish group, separately for breakfasts (n = 1462), lunches (n = 1504), and dinners (n = 1500). The diet quality of each dietary pattern was assessed using the Healthy Eating Index 2015 (HEI-2015) and Nutrient-Rich Food Index 9.3 (NRF9.3). The extracted dietary patterns were as follows: ‘bread-based’ and ‘rice-based’ for breakfast; ‘bread’, ‘rice-based’, ‘ramen’, ‘udon/soba’, and ‘sushi/rice bowl dishes’ for lunch; and ‘miscellaneous’, ‘meat dish and beer’, and ‘hot pot dishes’ for dinner. For breakfast, the HEI-2015 and NRF9.3 total scores were higher in the ‘rice-based’ pattern than the ‘bread-based’ pattern. For lunch, the HEI-2015 and NRF9.3 total scores were relatively high in the ‘rice-based’ pattern and low in the ‘ramen’ pattern. For dinner, the HEI-2015 total score was the highest in the ‘meat dish and beer’ pattern, and the NRF9.3 total score was higher in the ‘hot pot dishes’ than the ‘miscellaneous’ pattern. These results suggested that breakfast, lunch, and dinner have distinctive dietary patterns with different diet qualities. 相似文献
27.
Satoshi Oki Hiroki Kobayashi Hidejiro Kubota Taro Umezu Minoru Nagasaki Shohei Iwabu 《The Journal of foot and ankle surgery》2021,60(2):404-407
Pilon fractures with intact fibula have been associated with low-energy trauma. However, the compression force onto the ankle joint can damage the tibiofibular linkage as in a Maisonneuve fracture. Herein, we describe a case of a patient who had a pilon fracture (AO type 43 C3.2) without a fibular fracture. Three-dimensional preoperative simulation by reduction with the surface registration technique was performed as the fibular length was intact and there was no reference for the tibial length. The preoperative simulation revealed superior fibular head dislocation and shortening of the distal tibia. After emergency external fixation on the day of arrival, a 2-staged surgery was performed. During the first operation, the fibular head was reduced and the tibial posterolateral fragment was fixed to restore the tibia length. During the second operation, medial and anterolateral fragments were fixed in order to reduce joint surface of the distal tibia. In general, proximal fibular head fractures are easily overlooked. In the case of pilon fractures with severe length shortening of the tibia without a fibular fracture, a proximal tibiofibular injury should be suspected. 相似文献
28.
Summary Levels of serum tumor markers including tissue polypeptide antigen (TPA), CA 15-3, CA 19-9, squamous cell carcinoma antigen, carcinoembryonic antigen, -fetoprotein, and PAP were measured in 26 patients with bone metastasis and in 9 patients with primary bone tumors. More than one markers was elevated in 19 of the 26 patients with bone metastasis, although there was no elevation of the markers in 3 patients with renal cell carcinoma. TPA was the most sensitive marker in the diagnosis of metastasis. CA 15-3 was also a sensitive marker in this study, since metastasis from breast carcinoma may be the most common of all metastases in the skeleton. On the other hand, -fetoprotein was uniformly unresponsive except in one case of gastric cancer. Combinations of markers are valuable for metastasis screening tests. No definite correlations were found between the markers in this study. On the other hand, there was a slight elevation of the markers observed in two of the nine patients with primary bone lesions. Serum tumor markers are useful in the diagnosis of bone metastasis to differentiate it from primary bone lesions. Especially in solitary bone lesions, serum markers may be the only way to make a differential diagnosis between the two. 相似文献
29.
We used our new flow cytometric method to measure benzo[a]pyrene-diolepoxide-deoxyribonucleic acid adduct levels in peripheral lymphocytes from healthy male smokers and nonsmokers. Smokers who had pack-years of 20 or more had significantly higher mean benzo[a]pyrene-diol-epoxide-deoxyribonucleic acid adduct levels than nonsmokers. In smokers, the adduct levels were correlated significantly with age, years of smoking, and pack-years, whereas daily tobacco consumption was not correlated with adduct levels. We also found a positive relationship between age and benzo[a]pyrene-diol-epoxide-deoxyribonucleic acid adduct levels in nonsmokers. Passive exposure to tobacco smoke was not associated with adduct levels. The results of our study indicate that benzo[a]pyrene-diol-epoxide-deoxyribonucleic acid adduct levels may be closely related to aging and that tobacco smoking-as well as other environmental factors-may play a role in the benzo[a]pyrene-diol-epoxide-deoxyribonucleic acid adduct formation. 相似文献
30.
Kamada M Shinozaki S Sawamura Y Endo M Ohmi M Tabayashi K Miura M Zuguchi M Saitoh H 《Kyobu geka. The Japanese journal of thoracic surgery》1999,52(3):243-246
A 13-year-old girl was admitted with a sudden onset of chest oppression. Mediastinal teratoma was suspected on chest X-ray and CT scan. A grade 2/6 systolic murmur was heard at the upper left sternal area and cardiac catheterization showed mild pulmonary stenosis. After resection of the tumor, the murmur disappeared and histopathological diagnosis was mature teratoma. This is a rare case report of pulmonary stenosis caused by mediastinal mature teratoma. 相似文献