全文获取类型
收费全文 | 43227篇 |
免费 | 2069篇 |
国内免费 | 228篇 |
专业分类
耳鼻咽喉 | 476篇 |
儿科学 | 726篇 |
妇产科学 | 639篇 |
基础医学 | 5599篇 |
口腔科学 | 1365篇 |
临床医学 | 3210篇 |
内科学 | 10332篇 |
皮肤病学 | 1015篇 |
神经病学 | 3262篇 |
特种医学 | 1943篇 |
外科学 | 7159篇 |
综合类 | 264篇 |
一般理论 | 2篇 |
预防医学 | 1390篇 |
眼科学 | 669篇 |
药学 | 2903篇 |
中国医学 | 91篇 |
肿瘤学 | 4479篇 |
出版年
2023年 | 228篇 |
2022年 | 501篇 |
2021年 | 896篇 |
2020年 | 433篇 |
2019年 | 638篇 |
2018年 | 841篇 |
2017年 | 648篇 |
2016年 | 746篇 |
2015年 | 841篇 |
2014年 | 1123篇 |
2013年 | 1263篇 |
2012年 | 1966篇 |
2011年 | 2177篇 |
2010年 | 1213篇 |
2009年 | 1088篇 |
2008年 | 1887篇 |
2007年 | 2020篇 |
2006年 | 2046篇 |
2005年 | 2139篇 |
2004年 | 2044篇 |
2003年 | 1955篇 |
2002年 | 1999篇 |
2001年 | 1328篇 |
2000年 | 1470篇 |
1999年 | 1324篇 |
1998年 | 579篇 |
1997年 | 418篇 |
1996年 | 446篇 |
1995年 | 394篇 |
1994年 | 349篇 |
1993年 | 324篇 |
1992年 | 871篇 |
1991年 | 806篇 |
1990年 | 727篇 |
1989年 | 736篇 |
1988年 | 704篇 |
1987年 | 685篇 |
1986年 | 694篇 |
1985年 | 616篇 |
1984年 | 447篇 |
1983年 | 362篇 |
1979年 | 347篇 |
1978年 | 238篇 |
1977年 | 204篇 |
1975年 | 206篇 |
1974年 | 236篇 |
1973年 | 215篇 |
1971年 | 212篇 |
1970年 | 204篇 |
1969年 | 229篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
53.
The postnatal ontogeny of neurons containing different GABAA receptor beta (beta 1, beta 2 and beta 3) subunit mRNAs were examined in the rat thalamus using in situ hybridization histochemistry. Neurons containing beta 1 or beta 2 subunit mRNA developed remarkably postnatally, while most neurons were already strongly labeled with beta 3 probe at birth. However, beta 3 subunit mRNA decreased rapidly after birth, few cells being labeled with this probe at day 35 and thereafter. 相似文献
54.
Satoshi Yamamoto MD ; Yosinobu Sato MD ; Toru Abo MD ; Katsuyosi Hatakeyama MD 《Wound repair and regeneration》2002,10(4):241-244
Recently, we found CD3-CD4(bright) cells with comparative specificity for normal rat liver. In the current study, we investigated the type and form of both CD3-CD4(bright) cells and CD3-CD4(dull) cells in the rat liver. The surface phenotype of hepatic mononuclear cells in Lewis rats was identified by using monoclonal antibodies including anti-CD4, anti-CD3, and antimacrophage in conjunction with two- or three-color immunofluorescence analysis. CD3-CD4(bright) cells and CD3-CD4(dull) cells were examined morphologically using May-Giemsa staining and scanning electron microscopy. The distribution of CD3-CD4(bright) cells and CD3-CD4(dull) cells 48 hours after intravenous administration of liposome-encapsulated dichloromethylene diphosphate was also investigated. In comparison to CD3-CD4(dull) cells, CD3-CD4(bright) cells were slightly larger macrophages with abundant cytoplasmic granules, being present with comparative specificity for normal rat liver and showing negligible effects by intravenous liposome-encapsulated dichloromethylene diphosphate administration. These data suggest that in normal young rat liver these CD3-CD4(dull) and CD3-CD4(bright) cells may be dendritic cells and Kupffer cells that shift from the liver to the spleen or vice versa. These cells may also be able to locally proliferate in liver or spleen due to changes in the developing liver. 相似文献
55.
56.
57.
Makoto Watanabe Takashi Fujimoto Masayuki Iwano Hideo Shiiki Shinobu Nakamura 《Nihon Rinshō Men'eki Gakkai kaishi》2002,25(2):191-198
We describe the case of a 61-year-old woman diagnosed with primary Sj?gren's syndrome (SS) after an 8-year history of IgA nephropathy and a 3-year history of recurrent purpuric rashes. Her two daughters had previously been diagnosed with other autoimmune diseases. One daughter had Graves' disease and the other had Hashimoto's disease and systemic lupus erythematosus. The diagnosis of SS was made based on dryness of mucous membranes, Shirmer test, and parotid sialography. Thrombocytopenia, high platelet-aggregated IgG (PA-IgG) level, and normal megakaryocytes count in bone marrow suggested that her recurrent purpuric rashes were due to idiopathic thrombocytopenic purpura (ITP). Patients with SS may develop other autoimmune diseases. This case aids understanding of the immune pathogenesis and genetic background of SS. 相似文献
58.
K Hashizume M Sato S Saeki S Takamoto Y Mino T Onishi 《Nihon Ronen Igakkai zasshi. Japanese journal of geriatrics》1991,28(6):817-822
An elderly case of systemic lupus erythematosus (SLE) with suspected hemolytic anemia was experienced. A 70 year-old female was admitted to our hospital on December 31 with complaints of herpetic eruption. She complained of arthralgia since 3 month prior to her admission. The positive findings on examination were skin eruption in the left chest, a systolic heart murmur and a palpable elastic hard liver. Laboratory data showed raised erythrocyte sedimentation rate of 149 mm per hour, decreased Hb (10.1 g/dl), decreased hematocrit (30.0%), increased reticulocytes (33%1000), decreased thrombocytes (73,000/mm3), increased gamma-globulin (33%) and positive rheumatoid factor. During admission, she developed anemia. A stool test for occult blood was negative. The haptoglobin was 38.8 mg/dl and bone marrow aspiration showed increased erythropoiesis, suggesting features of immune hemolytic anemia, except she was negative on Coomb'test. Eye fundi were similar to case of typical bleeding observed in SLE. Concerning immunological findings, the antinuclear factor was x 1280 and the anti-dsDNA antibody was x 80, on which a diagnosis of SLE was based. She experienced numbness of the left arm and developed left hemiparesis 2 days later. Therapy with 15 mg/day prednisone obtained a good response and anemia, abnormal immunological findings and hemiparesis disappeared. 相似文献
59.
K Tsuji P Gopalan K Lehmann M Kimura A Horiuchi K Sato P D Lotlikar 《Cancer letters》1992,66(3):249-254
Species and sex differences of aflatoxin B1 (AFB1)-induced glutathione S-transferase placental form (GST-P) positive single hepatocytes have been investigated 48 h after an intraperitoneal injection of AFB1 to young male and female Fischer rats (2 mg AFB1/kg body wt) and male Syrian golden hamsters (6 mg AFB1/kg body wt). The presence of GST-P positive hepatocytes was examined by the immunohistochemical method. Male rats formed three times as many AFB1-induced GST-P positive hepatocytes as females. Pretreatment of both male and female rats with an inhibitor of GSH synthesis, buthionine sulfoximine (BSO) (4 mmol/kg body wt), 2 h and 4 h before AFB1 injection increased AFB1-induced GST-P positive hepatocytes by about 120% above the controls. Male hamsters formed several-fold less AFB1-induced GST-P positive hepatocytes than male rats. Pretreatment with BSO did not increase AFB1-induced GST-P positive hepatocytes in hamsters even though it produced an increase in hepatic necrosis. It appears that GSH and GSH S-transferases play an important role in modulating hepatic AFB1-DNA binding and AFB1-induced GST-P positive hepatocytes in rats and hamsters. 相似文献
60.
Masayuki Mano Akira Sugawara Yasuo Nara Kazuwa Nakao Ryoichi Horie Jiro Endo Hiroo Imura Yukio Yamori 《Clinical and experimental pharmacology & physiology》1992,19(12):795-801
1. Effects of potassium (K) supplementation (100 mEq/day) on urinary sodium (Na) excretion and on the secretion of atrial natriuretic polypeptide (ANP) during salt loading (350 mEq/day) were studied in 12 healthy salt-resistant normotensives under strictly controlled metabolic ward conditions. 2. Urinary volume and Na excretion on the first day of the high salt period (HSP) were significantly greater in the K-supplemented group (KG) than in the control group (CG). 3. There was a significant gain in bodyweight after salt loading in both groups, with a significantly greater gain in CG on the second day of HSP. Haematocrit decreased significantly during salt loading in both groups, the degree of which was significantly greater in CG. 4. Plasma norepinephrine decreased significantly during salt loading in both groups, the degree of which was significantly less in KG than in CG. A significant increase in plasma ANP was observed in CG on and after the second day of HSP, while a significant increase in plasma ANP was observed on the fifth day of HSP in KG. 5. These findings indicate that K supplementation accelerates diuresis and natriuresis, resulting in moderate suppression of volume expansion induced by salt loading and that this accelerated diuresis and natriuresis is not a result of the action of ANP. 相似文献